Mass Effect 1 vs Mass Effect2: Genesis?

So recently i just got interested into mass effect and ended up borrowing the first mass effect 1 and i bought the second mass effect 2, the thing is that i had to give mass effect 1 back because i friend moved and i only got up to Feros. The gamestop near my house doesn't have any mass effect 1 copies whatsoever and won't ever again unless someone trades their copy in or something. What happens if i get ME2: Genesis from the xbox live marketplace and choose my decisions from there? I basically spoiled mass effect 1 for myself already so that i can have an idea of what choices i'll make, for example, ashely was a racist and i used kaidan in my squad more so i was planning on saving kaiden on i think it was virmire? I was also going to save the citadel and place udina as the ambassador since the other guy is a prick. I have some what of an emotional piece set in place. Should i try to find me1 elsewhere? Or just buy ME2: Genesis?