Schoolhouse Tunic - HELP!

As I mentioned a few months ago, I participated the Sew Liberated Schoolhouse Tunic Sew-Along that Rebecca from Sew Festive Handmade was hosting.  I kept on track with the cutting, but with work and business trips, I got a little behind. Rebecca's tunic was complete - tailored and all - and I hadn't yet sewn a stitch.  So I buckled down last weekend and constructed the entire thing - AND IT'S AWFUL!

Now, the instructions were great - I had a little trouble in some places, but mostly because I wasn't reading the directions carefully and/or because I'm new to garment sewing.  Also, I decided to be fancy and use french seams throughout (I'm actually really pleased with this part).  So I think overall that it is well-constructed, and for the most part I had a good time making this (though I did have to break out my seam ripper more than I liked). The main problem with the garment is just that it's HUGE in the waist.  I can't believe I'm actually about to post the following pictures online, but I feel like I have no choice.  I'd really like to be able to wear this dress (oh yeah, I extended it into a dress), but I absolutely cannot do that in it's current state.

A disclaimer before we begin - I have not yet tailored the garment.  I feel like I need to get the fit correct before I'll be confident enough to go hacking a bunch of fabric off the sleeves and skirt.

Okay - deep breath - here we go:

As you can see, it doesn't look all that bad from the front. It's definitely a bit reminiscent of my grandmother's housecoat, but I feel like removing some fabric from the sleeves and skirt will help with that. Also, I've only finished the left sleeve (more on that below).  It's definitely a bit roomy in the top, but I don't entirely mind that.  I'm not really a tight-clothes kind of girl.

Here is where the problems start coming in.  From the back, I look like Miss Trunchbull from Matilda. If I gather the fabric in the back, there's about 6 inches too much.  But I can't really take the waist in any more because - as is with no elastic or closures of any sort - it just squeezes over my shoulders, which are quite broad.

And more heinousness.  The left-hand photo shows the side-view as is.  There is just way too much fabric.  I have enough volume in the hips - I do not need my clothing to add more.  The photo on the right is what it looks like if I gather the fabric in the back.  So much better.  And definitely less frumpy and nightgownish.

So, those are the problems.  As I've said, I have zero garment-making experience, so I really have no idea how to fix this.  Just from reading through blogs and wearing clothing on a daily basis, I have come up with a few possible remedies, but again, I have no idea if any of these are even feasible, let alone how to execute them.

1)  Remove the pleats in the skirt - okay, this one I do know how to do and will be doing.  The pleats just add too much volume for my body.  I need a straight skirt.

2) Add shirring or elastic to the back.  Would probably have to remove some fabric as well.  I'm not 100% sure what shirring is, but I think it has to do with elastic thread.  No idea how to do it. As for the elastic, maybe I could somehow make a little casing in the back because I don't think I'd want it around the entire waist, but not really sure how to do it in a way that wouldn't be completely obvious.

3) Add a zipper.  At first I was thinking a side zipper, though I'm pretty sure that would involve taking most of the garment apart, and then I'd still have the problem of too much fabric and figuring out how to get rid of that in the proper proportions.  Then this morning I had the bright idea of adding the zipper to the back rather than the side seam.  Still would need to remove fabric, but hopefully not deconstruct the entire garment...  Also, I'm great with zippers in pillows and bags - not sure about clothes...

Okay, so I guess I really just have two ideas - elastic and zippers.  Any other suggestions?  Or tips/tutorials on how to actually add elastic/zippers?

As for the finishing.  I originally cut the sleeves to be long, but after trying it on it was just too much fabric.  You think it looks like a nightgown now, imagine long sleeves!  The sleeves (well, the left sleeve) is currently hemmed to just past the elbow:

But I'm not sure I like that.  It either needs to be a bit longer (it's a pretty deep hem so I can let it out another inch at least, maybe even more) or shorter:

I think the idea of short sleeves, but I'm I'm not convinced that they'll look right.  I rolled this one up a bit, but I think even shorter would be better, no?

And I'm definitely going to take the skirt up quite a bit.  It's much better shorter.  I think I really just need to get the waistline/fit issues sorted out to better judge the rest of the dress.

So, can you help me?  Any suggestions would be amazing.  Links to tutorials would be even better.

Also, to end on a less complainy, woe-is-me tone, check out these amazing (and delicious) pretzel rolls Mr. T made.  The recipe is here.  I found it on In Color Order - Jeni has some great tips and tricks for getting the bread to turn out well.