minecraft lag help?

[Quad-core_i7]

having very bad lag problems and frequent crashes when I try to play minecraft on my pc.
system specs for this pc are as follows;
os: windows xp home
proccessor: intel celeron d 3.2ghz
gpu : cant remember atm but its an nvidia with 128mb gfx memory
ram: 256mb ddr1 182-pin ram.
my minecraft settings are everything off with short render distance and no sound as well as having optifine installed.
what should i do or upgrade to fix the lag?
if you need more info i will try and find out.

 

[Aastii]

You will need more memory and a graphics card that will have OpenGL support

 

[Quad-core_i7]

any reccomendation on a VERY cheap gfx card?
already know what memory in getting, just need a decent gpu now.

 

[Aastii]

What power supply, motherboard and case do you have?

 

[Quad-core_i7]

not sure off the top of my head, if it helps it is a standard hp pavilion t530.
motherboard: MS-6577 v3.1 Neon
anything using the same power as a geforce 5200.
case dimensions 38.1 cm x 19.1 cm x 41 cm
its hard to find out specific parts cos a) its 8 yrs old and b) it isnt a custom or anything.

 

[Aastii]

You will need a new graphics card, PSU, case and motherboard, and with that comes new CPU and memory. Basically, you will need a full new system.

Normally a simple upgrade of one or two components would be enough, however because of the age and because parts using those old standards aren't manufactured any more, and are too overpriced anyway.

 

[Quad-core_i7]

thank you very much aastii.