Hmm, how can I tell if the PSU will fit in the case? It says it is a EPS12V? I've never heard of that format.
I'm pretty sure your PSU and case will play nice. The PC P&C Silencer 610w, that you chose isn't that big. And the Antec is pretty big for a mid tower. If that case can fit an 8800Ultra, it can fit that power supply.
EPS12V is a power supply standard that limits the output of all the 12V rails to no more than 20A per rail. A lot of people use this power supply for their PCs. So don't worry about it.