" 802.11N AT&T wireless router with DSL modem. "
You already have a modem for your DSL. I hope they're not trying to sell you another modem with your new router. SeekingKnowledge is right, you want an N router, which is what is meant by the N after the 802.11. Usually it's a matter of sticking the wires in the right spot, and then putting a CD in your PC to tell you how to set it up. It's easy.
If you have At&T Uverse available in your area, get it to replace Dish. That might save some money.
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I thought getting old would take longer.