Upgrading performance on my laptop

I have an HP Pavilion dv6707us laptop with these basic specs.

1.9 GHz AMD Athlon 64 X2 Dual-Core Mobile Technology TK-57 CPU 

3 GB RAM

160 GB 5400 rpm SATA Hard Drive

nVIDIA GeForce Go 7150 Graphics Card

It runs TF2 okay, but when there are more than 8 people on the screen at one time it starts to lag. I have gone to "canyourunit.com" and several similar sites. IT appears that the weakest aspect of my computer is the Graphics Card. I have confirmed several times that I can get a better graphics card on my laptop, if I also get a new motherboard to match. I know that this is very rare among laptops, but once again, I have confirmed with HP several times that my specific model can in fact get a better graphics card.

Now, because my laptop is no longer under warranty, and also because HP would have to install a new graphics card, motherboard AND charge for the services, the cost is looking to be about $250. I just wanted to double check if the upgrading the graphics card would improve my performance.

And please, don't post saying that I should just get a desktop computer.

If the company is offering to upgrade you, a new GPU won't help as much as a boost in CPU performance. TF2 relies more on the processor than graphics card, so a speed boost there would be more beneficial. You might just try using an FPS script, but those make the game look pretty terrible. I'd say that $250 laptop upgrade for only a GPU isn't worth it. If they can do a CPU upgrade, that would be worth it.

To summarize, a new graphics card would help, but not much. The preferred upgrade is a new processor. But I have no clue if HP would do that.

Yeah, nevermind. I called HP and found out that getting the necessary motherboard would cost around $350, a compatible graphics card would be about $100, and the service charge of $150 would bring the price to $600.

Yeah, not getting a new graphics card.

Big waste of my time.

Something I've found that helps:

Run in windowed mode, bout 2/3 of your screen instead of fullscreen. Helped my FPS and lag considerably.