As for the installer question, what part of town are you in?
As for the receiver question, and I'm assuming you have a Shaw Direct receiver, it might depend on how you obtained the receiver. If you purchased it from certain retailers in Canada or the US, they should have given you some advice about a broker, or offered you the broker service themselves. If you obtained the receiver thru some other means, you need to know that you cannot activate it without a Canadian address that Shaw calls a "service address". It cannot be a PO Box address. Again, the most painless way to go about getting a Canadian service address (assuming you have no friends or relatives in Canada to help you) is to use a broker (see sticky thread "what is a broker".) If you want a broker name, let me know and I will PM you. There are other individuals in this forum that have obtained a service address by other means, but I'll leave that to them to respond.
As for the switch question, I'll have to leave that for the tech savvy, except to say that I have Cox Cable and Shaw Direct going to the same TV. There are 2 coax inputs on the back of my TV, and a built-in A/B switch, and I switch between one and the other using the remote. Also, I believe I'm correct in saying that you cannot use a Direct TV dish for Shaw Direct. You need either an official Shaw Direct dish (model 75E for Phx area) which will pull in signals from Shaw's 2 satellites, or optionally 1 or 2 generic dishes. Whether you use 1 dish or 2 will depend on what progamming you want, and whether you want HD or not. Maybe you knew all this.......?