Just called again. The guy said I have two options:
1) call the roadside assistance and have them arrange for a replacement vehicle (in that case, do I still get the same car?)
2) he said I could go to firestone or a tire person, get it fixed and then have Avis reimburse me. I really don't have time for this as I'm traveling for work. By the time I get done it's already 5. So that's a no go. Well only about 4 psi has leaked since the morning fill up. So maybe I'll wait till morning to see if it's low again.
Otherwise I don't know...
Any suggestions???