Upgrading Laptop

tI currently know my laptop is 100% authentic horse-pomegranate and needs to be improved.

Minus the shitty battery, I've considered a Ram and a GPU replacement. Yet I need some help on this part. I'm not very knowledgeable about laptops, yet I feel I can replace this myself, "though it seems sketchy". If anything, can Fiel or someone as tech savvy as him support me with this? I feel like this should be an open discussion on support.

Current info~
Laptop:Inspiron 1521
OS: Windows 7 64x bit
Ram: Memory Type: DDR2 PC2-6400, DDR2 PC2-5300, DDR2 (non-ECC)
Maximum Memory: 4GB
Total Memory Slots: 2
Chip: AMD Turion 64 X2 CPU - 1900 MHz (1.90 GHz) Dual Core
GPU: ATI Radeon X1270
Budget: 100~300 (less is prefered)

To be honest I know nothing about laptops graphics cards or their sockets, but I suppose they are all quite similar. I would say get a Radeon 6620M my friend has that it is pretty nooooice. And get two 4 gig sticks of RAM. With Win 7 64bit you can have up to 16 gigs but given your mobo... just get two 4 gig sticks, or even two 3 gig sticks. Corsair is a nice brand. Kingston too.