Help!!!

I was riding around Vancouver this morning and on my way back to my hotel I lost a bolt from my derailleur, and with it, the guide pulley assembly. (parts 7 & 8 on the diagram)



I was able to get it to stay in a single gear so I could limp it back. Tried to jury-rig something with parts from Home Depot but that's just getting me the 2 top gears instead of 1 middle gear.

Is it possible to buy just the missing parts or will I have to get the whole derailleur? How do I find out which specific model of the Alivio I have? (I can't find the manual online right now.)

If I end up replacing the whole derailleur should I just replace the stock one or can anyone recommend a different one?

Guess I probably won't be bringing it on next week's business trip (San Diego).

Oh, here is where I was riding this week:

Tuesday (~24-mile loop from downtown around UBC, down near the airport and back through midtown):


Today (~20 mile ride from downtown, through Stanley park and across Lions Gate Bridge to North Vancouver and got in a little climbing in the foothills, sadly not enough time to get up into the mountains, although probably a good thing as it turned out):