and i believe if u change ur PSU u need a Case that is compatable with it
who u recommend me some cases
a cheap one for the cosair tx550
Not necessarily. Although if you are in the market for a new cases, there are some cheap great cases like the Cooler Master HAF912/Elite 430/Elite 431, Corsair 200R/300R/400R, Antec 300/1100, Bitfenix Merc/Shinobi/Raider, NZXT 210. Those are great case for airl cooling and not very expensive.
The GPU is compatible with your motherboard, no problem on that.
Clarify something for me. What parts do you have now (I would suggest you list them)? Is that $1,000 for an entire build or just the 4 parts (motherboard, GPU, PSU, SSD)?
We could list better components afterwards if we know your entire system.