What Geoff says is the only way around it, but you are likely to lose enough sonic quality that you won't like it.
Unless the burn process is done shitty, she should be able to rip as high a quality of MP3 as she wants (use the preferences Ali) so, this reminds me of Bob Marley, "Burning and Lootin'" but I guess it's "Burning and Ripping" instead!
Here's the problem: mp3, aac & wma aren't just different but equal file types, they also correspond to different codecs (compression/decompression schemes). By definition a codec converts a large .wav file into a much smaller file and the laws of physics dictate that a little bit is lost in the process. If you go up and down between between .wav & only one codec the resulting 2nd generation .wav will have a little less fidelity than the original .wav, but this won't be cummulative over mulitple iterations. However if you go up and down between different codecs you lose a little bit of different stuff each time & it
IS cummulative. This may or may not be something that you notice, depending on how picky an audiophile you are & the fidelity of your listening equipment, but do it enough times & it will degrade the overall sonic quality. I have heard that this is worst when trying to go between .wma & .aac, less so when going between either & .mp3.