All you need is 2 kinds of tweezers which you probably have around the house, or get from any dollar store.
I replaced the D40x focusing screen myself, and removed and realigned several times too. Very simple process. a 2 minute job. You can ask to buy the part from Canon. But personally, I would go for a third party one with a manual focus prism built in.
However if you are not hands-on kind of person, and you want peace of mind, let CSC do it. But I doubt they will agree to install a 3rd party screen with MF prism in it.