Its by no means going to be a cheap or easy task, and depending on its condition you might need a 2nd car as a donnor, or be left buying lots of very expensive parts.
The UK is the only real source of parts, but there are specialist wreckers in the US and Canada.
Anywhere else in the world will require some very crafty searching, and of course joining your local Triumph car club is a must if you ever actualy want to complete the car.
The knowledge and experiance of its members will be essential.
http://www.rimmerbros.co.uk/ rimmerbros is a long established supplier of classic british car parts, and should you give some idea of whats avliable.
Use
www.google.com and
www.yahoo.com to search for Specialost Triumph sites, many of which exist, and many of which include complete rebuilds of cars.
There is also a Triumph Car magazine, but its hard to find, being printed in the UK, if you can source a few copys they are also very imformative.
The TR2 is a true classic car though, and worth a fair bit in any condition, what ever you do make sure its with in your limits.