AirPort Help

I just got a new iMac, and it has a Airport installed,i was trying to connect it to internet, but it can't find a network, i have wireless router "linksys", and i can get it to work with a cable, but having a imac i was hoping to get rid off all the wires.Do i need anything else wit my computer or am i just plain dumb.
Please help he, i am so new to apple, but i want to become its bigest fan(the design is soooo cool)

 

yes is on, but i don't know if the linksys is lockedeek, and no it does not see any networks, i was trying to find my network name, but here again i hit the brick wall. If you can would you write the directions from a to z, i feel like i need the info explained like to 3 year old.
My main computer is a Dell, does this have anything to do with it?