Trying to connect a modem/router to another router

Hey, i have a d-link DSL-500T moed/router and can currently only use
one pc at a time with it and tried to connect a Lynksis wrt54G wireless G
router to it but cant seem to get it …..tried searching similar questions
but keep getting stumped…..can anyone help? please?
just incase you are wondering i want the network to go something like
this
PC—>Lynksis Wireless router—>D-link modem/router—>internet
oh and this is using both the MAC and Windows trying to get it to work
on both types….thanks.