Just to state: I <3 MegaMan.
My own fabric choice would have been spandex, as Roll's clothing is VERY tight, but I give you kudos on finding the right pink. I suggest as stated before to add another layer to the top since it's not so flimsy, and even take it in so it fits you better and sticking a zipper on the side or back. Also, I think it would add to the effect of the "bodysuit" if you attatched the top to the 'underware' part. The jewel looking thing on her chest is a raised peice. The gold bands on the gloves are 3-dimentional, as are the ones on the ends of her boots. Also, on Roll's back, she has this plug looking thing like a tail, maybe about two inches outwards. Occationally she is drawn with a patch on her back that has some writing on it, but i've never seen a good capture of it, so.. no biggie. Putting some elastic in the thigh highs would help keep them up, or even just make some securing stitches to the undersuit. I LOVE the boots. Are they painted rain boots? You need to let em know how you did that. ^_^ The hair turned out really well as well. I also like the helmet, but the disks on the side should be closer to your head if possible, and the transparent yellow 'antennae' should be a little longer and stick out some more.
Sorry to be so nit picky. I hope this helps you some in making the costume more acurate.
Only a couple things. There should be a darker blue stripe down the middle including the collar of the turtleneck, The shirt should be a lighter green, and the shoes are a dark red. More like the colour of the carpet in the background, actually. I can't see if she has the pin in her hair, so if not, that too. I love the skirt. Might be better as a darker pink, but the colour kinda fluctuates in the anime a little.
I hope I helped ya! YAY .EXE COSPLAY! ^_^! I have some images of the tail peice and some other things on roll, if you would like to see them. Just PM me.
Keep up the good work!