Just a word of caution. If you router is downstairs and your computers upstairs powerline adaptors may not work. People tend to think just because they work over your mains they will connect to another anywhere in the house.
If you have a ring downstairs and a separate ring upstairs there is no way you can connect the two together with powerlines.
To explain in my house the downstairs is connected by one mains ring. So at my fuse box I have a fuse for the downstairs power sockets. Upstairs power sockets have a seperate fuse. So both rings are not connected together. Therefore if I put a powerline adaptor upstairs and one downstairs they cant see each other because they are on different power rings. There is no cross over. Really you need to check your fusebox and see how your mains goes round your house.
However if I put two powerlines downstairs as they are on the same ring they can see each other.
I didnt realise this till I did some research. In the end I put Cat 5 cable from downstairs to upstairs once I had worked out a route and its the best thing I did.
Just something to bear in mind when thinking about powerline adaptors.