Graphics Card/PSU Upgrade Help

Hi, I'm in the process of upgrading my Computer and wasn't too sure what graphics card and PSU I should get. First off, these are my specs:

Manufacturer and Model - Acer Aspire T180
OS - Windows Vista Home Basic SP1 32 Bit
CPU - AMD Athlon 64 Processor 3800+, 2.41 GHz (Single Core)
Graphics - Nvidia GeForce 6100 nForce 405 256 MB Chipset
HDD - 160 GB Serial ATA
RAM - 2 GB System RAM (1 GB Kingston DDRII, 512 x2 Acer DDRII)
Motherboard - Acer
Monitor - 17'' Widescreen Acer LCD, Native Resolution 1440 x 900
PSU - 250 Watt Max output (Yes, that stinks, I know.)


What's a mid-high range (doesen't have to be the absolute best but what's good for gaming) card/PSU that you would recommend? This chipset has to go as well as the PSU. I looked around on sites 'n forums but can't get a good answer. I also have PCI-E x16 if that helps as well as AGP slot on the motherboard.

I purchased this system in September 2007. Any help is appreciated. (Made this thread at like 2:11am, -8:00 but will post back after I have slept. Also didn't know where to post this but hope this is right.)