CSR is my favorite resort and I did get to eat breakfast at the Maya Grill -yummy!!! I love everythinng about CSR. I have never stayed at ASMu, but I have stayed at ASMo and ASSp.
Try to stay at CSR. Perhaps a family member can lend you the money until you have it.....
If all else fails andn you have to stay at ASMu, all I can say is.... good for you and I'm sure you will still have the BEST time!!!!! check out some of the pictures at wdwig.com. There isn't a section at this resort that isn't cute. The All Stars have all you need... great gift store, arcade, one of the BEST food courts on property, a pool bar, hair wrapping, great buses, great pools, and Disney magic. I love the All Stars because they make the seemingly impossible (having a "Disney resort" experience at an affordable price), possible!