rip it again, just do a better job.How good is the original?If you can get 480x320 resolution and an average bit rate of of 900 or better when ripped it should look good.Depending on who the copies are going to you could save some space and rip it into divx or mp4 format.
if you want free software to do this kind of thing linux is the way to go, all this can be done for free with linux