Good Power supplies for my computer?

This one should be enough for your needs -

www.newegg.com/Product/Product.aspx?Item=N82E1681737103...

Check with the fittings though. Companies such as Dell, HP sometimes use measures preventing any outside components (especially PSU, motherboard) to not fit in.

As far as fit goes I wouldn't be too concerned, you should be able to fit any 500w unit out there. I'd be more concerned about power needs.

EDIT: Emperus is right, though I didn't have any problem the one time I replaced the PSU in an HP, it was standard atx.

Would emperus reccomendation work with a 400 watt graphics card without overheating? Sapphire HD 4650 if more detail is needed? Don't need any info on the card just wanna know if 380 watts would be able to handle it.

The Antec unit will power your rig no problem. The 4650 has very low power consumption.

You can always opt for higher wattage units depending on your budget. For an HD 4650 rig though, that Antec unit will be enough.