OK, I bought the Linksys one. It has an additional RJ45 port, for internet - I think the model is called broadband router. But I couldn't run the setup (came in CD). Anyway I gave up installation and used their web based admin instead. Then I removed cable from that internet-RJ45 slot and plugged in one of the four normal slot and followed infra's tutorial. Worked great
and I am so happy.
Files and internet is shared between 2 PCs and one Laptop now. One PC wired, one PC and laptop wireless. All great, and infra, special thanks