Im not exactly computer savy but i do enjoy playing rome total war but im not sure if my computer could run empire total war

i have a compaq presario pc sr5002hm desktop

Memory

Component Attributes

Memory Installed 512 MB

Maximum allowed 2 GB (2 x 1 GB)

Speed supported PC2-4200 MB/sec

Type 240 pin, DDR2 SDRAM

Hard drive

120 GB SATA 3G (3.0 Gb/sec)

7200 rpm

memory-512mb

harddrive-120gb

graphics-intel graphics media accelerater 950

Empir Total War specs:

Supported OS: Windows® XP Service Pack 2 or Windows Vista™

Processor: 2.4 GHz Intel® Pentium® or greater or AMD® Athlon® equivalent CPU

Memory: 1 GB RAM (XP,) 2 GB RAM (Vista™)

Graphics: 100% DirectX 9.0c compatible hardware accelerated video card with shader version 2.0 support, 256 MB video memory

Display: Minimum screen resolution of 1024 x 768 pixels

Sound: Directx9.0c compatible sound card

Hard Drive: 15 GB free hard disk space formatted as NTFS

Peripherals: Windows compatible mouse and keyboard

im not sure if this is enough info and should i buy a graphics card and if so how much do they cost

oh and i dont think i have enough RAM so how much does it cost to buy RAM or whatever its called