As gisuck said, only 1-11 are allowed in north america (under most conditions). Any regular router, or even commercial router, sold for/in north america, should only have 1-11 (If you do have one or seen one that has more, it was likely sold outside of north america)
A good program, if you think you are experiencing wireless issues from other wireless access points, is inSSIDer.
This program will scan all the area, and and show any access points it can pick up in range.
it has multiple graphs/displays to show overlap etc.
http://www.metageek.net/images/products/inssider-landing/inSSIDer-For-Home_Product-Page_vid_on.jpg
This can allow you to adjust yours to keep it out of range of others in use.
Your best by default choices are 1, 6, 11. Choosing any of these, say 1, you would get ZERO interfearance from 6, and same 6 to 11.
Many routers by deafault are on 6 or 1... so if people havent changed their settings, you should be able to choose one with no interfearance.
If not, you can at least, use this to choose one with the LEAST interfearance.
