samsung galaxy s3 sprint version in usa

[bumpybus]

I have a samsung s3 sprint version usa located need a download for os onto micro sd card I dont have a computer and am stuck using my 7 year old sons phone factory reset did not work

 

[hang-the-9]

Stock ROM is here http://forum.xda-developers.com/showthread.php?t=1737859 You can probably download it directly to the card, but I don't know if you can setup the flash of the ROM without a PC.