Want to upgrade my new a6703 pavilion, Power supply and graphics questions

I just purchased hp pavilion a6703w that came with nvidia 6150se graphics and want to upgrade. I emailed hp and they told me i only had a 250w power supply and would have to upgrade that first. Dissappointing that i paid almost $800 and got such a carpy power supply. Anyway how do i find a power supply online for my computer? I there any graphics cards under $60 i could try for gaming? This is the specs hp said i have in thier email to me:
Pre installed power supply is 250W.
* Input voltage - 100-127v/8A
200-240V/4A
* Maximum output wattage - 450W

The limiting factor for putting any decent gaming graphic card into your system is that 250w power supply. There's really no graphic card that will provide decent gaming performance that won't use more power then that 250w can put out. You can upgrade that power supply with a good quality 400w to 500w for about $50-$60. Don't get some cheap garbage power supply (Raidmax, Apevia,Linkworld,StarTech etc.)
Decent ones would be.
http://www.newegg.com/Product/Prod [...] 6817341020
http://www.newegg.com/Product/Prod [...] 6817104052
http://www.newegg.com/Product/Prod [...] 6817256032
http://www.newegg.com/Product/Prod [...] 6817702014
http://www.newegg.com/Product/Prod [...] 6817139003

The addition of a decent power supply would enable you to go with a more powerful graphic card. The PSUs i listed would be fine for a HD4670, 9600GT,9800GT, HD4830 possibly higher depending on which PSU you pick. Be aware that your HP doesn't have very good cooling and it's something you'll need to keep an eye on. Download a hardware monitor and keep an eye on your temps. Some cards may block 1 or 2 of your SATA ports, you'll either need to move the connectors or get aftermarket connectors so they'll fit.

*EDIT* the best graphic card i'd use with your system WITHOUT changing the power supply is a HD4650.
http://www.newegg.com/Product/Prod [...] 6814102805
http://www.newegg.com/Product/Prod [...] 6814141080

I've done several upgrades on the HPa67XX series and they use a standard ATX power supply.

I really suggest that you upgrade that power supply now. I do not know what went wrong with mine, but I had it for 3 weeks when the power supply just made a loud popping sound and then the tower would not power on. I sent it to HP for repair. They said they replaced the power supply. Little did I know, that was not true. About a month later it happened again, except this time I heard a sizzling noise. I do not know what it was but some white stuff had melted all over the place inside the power supply box. I sent it back to HP only to have them tell me that they were going to nullify my warranty . I had not even owned this computer for 3 months. When I received my (still not working) tower back, I opened it up and looked at the power supply. I could not believe it was such a crappy one. They had also not replaced the power supply from the 1st time like they said they did. The tape was broken and there was a repair date stamped on it. Well I just replaced it myself and it has been about 3 weeks now and (cross fingers) no problems. I used Okia ATX 450 w. Hope this helps.