Can DSL be used with phone extenders?

DSL connections are pretty much limited by technology to no more than 17,000 feet from the central office or remote POP where the copper-to-fiber link is located. The only way you can answer your question is to talk to your prospective service provider and ask them if they can deliver DSL to your premises (wireless phone extender or not). Give them a call and ask them to measure you for DSL: they'll be able to tell you pretty quickly whether or not you can get such service installed.