Amp Tubes Class 101 - I need help!

Hey Guys!
Here's the scenario: It's garbage day and I'm headin' down my street to take my kids to school and I see a bunch of amps in someone's garbage pile! I pull over and throw 'em in back of my van without even looking what exactly they were (the garbage men were only about 6 houses down). Anyway, what I salvaged here is 2 fender heads (Bassman 50) and a Music Man 112 RD "Fifty". As soon as I got home I plugged everything in and allowed the tubes to warm-up. I plugged in my guiter and tested the 3 units. One fender amp head worked great! The other works, but has some problems - I can fix those. Unfortunately, the Music Man amp didn't work at all. I inspected the back and sure enough ALL the tubes are missing. I am on-line trying to find out what tubes it uses. Can anyone enlighten me on what tubes it uses. I am actually a drummer who dabbles in guiter so I do not know that much about amps. I don't know if I can just go into a music store and say "I need all the tubes for a MM 112RD-50 " Will they know what I need? I'd rather go in knowing what I need. The music man speaker sounded GREAT when I ran the fender heads through it so I am looking forward to repairing the unit. I first need to test it out with all the tubes present. The unit just needs to be cleaned-up. I'd appreciate any help. Thanks!
Lonnie

Sorry about the typos - guiter-guitar !!

OK -I overlooked the tube chart inside the amp. It has most of my answers. I also have a good idea of what brand to use after reading many of the posts on this website. Any thought on fuses??
There was a 3a 250v fuse in it (blown)when I got it and it is supposed to have a 3a 120v fuse. I can't ssem to locate any 120v fuses. Will I damage the unit if I use the same fuse as the previous owner (250v)? Maybe that's why it was in the garbage???? Most of the amp is pretty clean now. I truly believe it is well worth fixing (even though I'm not a guitarist).

Man! How come that stuff does not happen to me? Great score!
What ever you do, don't throw those amps out. Even if they are toast, someone is going to need parts.