Can not use Internet with new Linksys rangeplus...

Question

I'm using HighSpeed Internet of AT&T and the modem is 2WireGateway. Now I have 2 laptops Sony Vaio VGN - CR 220E and Dell Inspiron 1525, so I bought Linksys rangeplus wireless router to use Internet wirelessly. I run the CD to install into my laptop and then did all the steps correctly. The installation was completely successful, but I cound not use Internet. I had to use the old 2Wire GAteway modem to surf Internet but it is not wireless. What can I do now? Please show me. Thanks a lot.