GDDR3 or GDDR5 Low Profile card that can run on a 270W PSU

Hi guys,

A few months ago I bought a Dell Optiplex 755 (Intel Core 2 Duo 3.0GHz, Windows XP, 4GB DDR2 RAM) and I believe it has a 270W original PSU. It came with an ATI Radeon 2400XT graphics card, which has 256mb memory and a core clock of 700MHz. However, the card is DDR2.

Now, all was fine until a few days ago when I replaced my 19" monitor (1280x1024 or whatever it was) with a 22" widescreen (1680x1050). When I did this, I began to experience problems as listed below:

1. "Virtual memory too low" message
2. Horizontal lines across screen moving up and down when I have a white background up. Is this called "tearing?" I changed the vsync but sometimes the problem still returns
3. Lagging in my game (Flyff, a F2P MMO) that wasn't there while using the 19" screen. I can tell that my game is having difficulty with this larger resolution.

So, guys, here's what I'm looking for:
- Can run on my 270W (lol, I promise I'm not a troll, this is a REAL question) PSU
- Is "low profile," as my computer is a slimline
- GDDR3 or GDDR5
- Has a faster clock rate than my current card (so more than 700MHz)
- Under $100

Any suggestions? Thanks.