Networking Question

How would I set up the second router to pickup the router that has the DSL plugged into it? I just want to make sure that it is possible to have the DSL plugged into the upstairs router which sends out the wireless signal. This signal will then be wirelessly received by the downstairs router. I will connect the XBOX to the downstairs router and be connected to the internet.

I know that when I bought my Linksys router it cost like 60 bucks or so and the XBOX wireless card is 100 bucks so if I can do it this way and save 40 or 50 bucks (another 60 dollar router instead of the 100 dollar wireless card), I would be pretty happy. Would it be complicated to get this set up or should I just be able to call tech services and have them walk me through it?