The CX series from Corsair is not a bad PSU ..... but its 9.0 performance rating doesn't exactly get em excited either. You store limitation curtails some recommendations as it doesn't offer as favorable pricing nor selection as is found on newegg.ca.
Was a time I said never bother w/ less than 650 watts as ya didnt save more than $5 if buying anything decent......4 months ago 650 watter PSU's were $60....now w/ all the lower power GFX cards, PSU manufacturers have reshuffled their prices and everythong is $90. Given ya situation, I'd get the Corsair.
The VX 430 is $25 on newegg.ca which wud be good enuff for a 7750.http://www.newegg.com/Product/Product.aspx?Item=N82E16817139026