Both my wheels have been nicked! Help!

net_buster Posts: 3
edited December 2011 in The workshop
Hi everyone,
Thanks in advance for anyone helping me out in this thread. First let me start out by saying i know virtually nothing about bikes :(. I've been the owner of a couple of carerra bikes from Halfords and that's about it.
I got both my tyres nicked on a carrera subway ltd edition which according to the website takes 26" wheels. After taking it to two bikes shops and getting a quote of over £250 which i definitely can't afford I've decided i'll have to buy everything second hand and do it myself. I've wanted to learn more about bike maintenence anyway since I love biking and use my bike everyday so i guess it's one way to learn. My Bike is my only way of transport and the way i usually get to work so it's a big of a nightmare without it

Anyway I'm really just looking for some guidance. Can i put 700cc tyres on my frame?? - i'm using the bike soley for road/city riding ATM so thinner tyres might be an idea since I have to replace them anyway.
Also it had disc brakes and is 21 speed - as I said i'm fairly clueless as to what information I need to supply so people can offer advice.
What parts will I need to get it up and running again? Is it even worth it or will it be as cheap to buy a new bike this Xmas when the sales on?