You could use more amps, but don't buy a cheap brand; save some more $$ for a better brand, such as antec, ocz, corsair, seasonic, or enermax. Cheaper brands overstate their specs, and can fail suddenly while under load. I suggest a minimum of 22 amps on each 12v rail. Corsair ps often have a single 12 amp rating of at least 30.
will my current psu be able to run 9800 gt?