Torque Converter Slipping

[ttzcar]

Oh the irony,... just as I was singing the X5's praises.
My torque converter is slipping. (2002 4.4) That's the reason my car was shaking/vibrating on the highway over 65mph randomly. I took some advice I read on this forum and it doesn't vibrate/shake as much if I keep it in Sport Mode. Here's my question and if someone with the knowledge can PLEASE help with a reply...
My torque converter has been slipping for about 3 weeks now, I'm wondering how long I can drive it like that or what to look for as not to get stranded somewhere. My rpms are only fluttering about 500 rpms right now. It's not too bad other than the violent shaking at higher speeds. I won't have any money to fix for about 3 weeks and I sold my second car 3 weeks ago (yup, sucks). Does anyone know approximately how long the X5 can run on a slipping torque converter before it finally gives up and moves nowhere? My commute to work is about 50 miles round trip and I've been managing just fine in the slow lane. Thanks guys.