Mind end gaming pc build

taiman

Honorable
Jul 26, 2012
2
0
10,510
hi i am new to pc building and want to make a pc capable of playing games like gta 4 on low settings or something like assassins creed revelations and i have a pc with has a good aopen case which room for 2 fans and 1 stick of DDR2 2 gb ram and a processor Intel core 2 duo CPU e7300 @ GHz wolf-dale with l1, l2 and level 2 caches and have a Intel g33/g31 express chip-set family gpu and no dedicated video card and a hard disk of 240 gb and 320 gb external hdd and a psc of 350 w the mother board is a Intel dg31gl i have a good dvd and cd drive and i don't need any external hardware but my LCD monitor has vga wire and no need for OS and also have a old PC with 3 sticks of ram around 1.50 GB and hard disk of 100 GB and some 4 year old Intel processor with mother board with a lot of USB slots
do i need to make a new computer from starting or update the hardware if i have to upgrade then i can spend around 200$ or 300$ and have so spare for buying more games and i have a 32 bit system

i found some sites for gpu, processor and mother board

http://www.newegg.com/Product/Product.aspx?Item=N82E16819103911
http://www.newegg.com/Product/Product.aspx?Item=N82E16814131441
http://www.newegg.com/Product/Product.aspx?Item=N82E16813138329

are they worth it or not