Help me with running BF3

Hello,
I was wondering if i could get help running Battlefield 3. I picked up this pc from a computer market or $100 its like xp or something. It only took 10 minutes to boot up.

Its pentium G4
512mb ram
128mb gfx!!!!!!!!
50gb hdd
AND FLOPPY DISK
Windows 2000 disk but xp installed

I was wondering if i could find a floppy disk which had battlefield 3 and where i could buy it to install on it. Im really looking forward to playing some full res games.