We have 2 computers in the same room and went over to Btbroadband and wireless at the same time and purchased the following.
1 Bt Voyager 2100 wireless router (this also contains the modem) and 2 Bt Voyager 1050 USB wireless networking adaptors. These work fine. This is all you will require. I do not have any knowledge of any other products
N.B. I originally purchased Philips USB adaptors and when I did have a minor connection/set up problem I found that Philips help was on line (rubbish) and Bt did not want to know because it was not a Bt product. So I took them back and exchanged them for Bt one's.
Bt products are more expensive but as I'm with Bt I thought it was the best way for me to go.
No idea about printer, but you must be able too that's the idea of 'wireless' but I think your computers will have to be connected via a network. Perhaps someone else will know.
I hope this helps?