I'd like to upgrade video card, but need a better power supply.?

I bought a Hp Slimline s5-1070t (s5zt) and would like to upgrade the stock 220W power supply to at least 320W, or 400W if any exists. I see many replacements for slimlines at ebay with the 24, 4, and 2 sata connectors I'd need, but are they non standardized for size or pin outs? Would it be possible to have an external power supply that I could run the connectors into the PC? Or am I stuck with the slow video card it came with?|||Yes, if you don't care about appearance, you can mount the power supply outside the case and run the cables into it. But be sure to attach a ground wire between the case and the power supply unit. And don't try to use both PSUs together.