I don't know much about computer hardware

but here's my system properties:

Manufacturer: Hewlett-Packard
Model: HP G60 Notebook PC
Processor: AMD Athlon Dual-Core QL-62 2.00GHz
Memory (RAM): 3.00 GB
System Type: 32-bit Operating System

...soo, do you guys think it will be able to run Fallout 3???

You've missed out an important point - your graphics card. Throw us the results of something like Piriform Speccy and we can tell you, though

Ok, I think I found it, it says NVIDIA GeForce 8200M G

and if that's not good enough, is there a way to get a better graphics card for my computer?

Would a nVidia 9800GT be good enough for Fallout 3?

It will run, but it will be fairly stuttery even on low settings. It really isnt very powerful. And since its a laptop it is not upgradable. A 9800GT would run the game fine, but you cannot place that inside of your laptop. The parts are not interchangeable in notebooks.

Ok, thanks