Are these compatible for my rig?

here is my rigs information from everest.

Motherboard:
CPU Type DualCore Intel Core 2 Duo E7200, 2533 MHz (9.5 x 267)
Motherboard Name Palit BI01
Motherboard Chipset Intel Bearlake G31
System Memory 1014 MB (DDR2-667 DDR2 SDRAM)
DIMM1: Samsung M3 78T2863QZS-CE6 1 GB DDR2-667 DDR2 SDRAM (5-5-5-15 @ 333 MHz) (4-4-4-12 @ 266 MHz) (3-3-3-9 @ 200 MHz)
BIOS Type AMI (05/22/08)

there are 2 slots of memory, I want to install windows 7 Ultimate 64bit, however I still don't know what memory and video card am I going to buy. I have a plan on buying:

PowerColor ATI Radeon HD4670 512MB 128bit PCIE
Kingston 2x2GB DDR2 800 (PC6400)

my question is the max memory that my motherboard can hold, and aren't this specs not bottlenecked to my system?

thanks a lot for the answers