Cable from wall to RG

I currently have U-Verse Internet/voice (no TV) using a 3801HGV RG. It was originally installed with a new wall jack in my den against an outside wall. AT&T supplied a 6 foot cable from the wall jack to the RG... it is round, beige, RJ-11 ends but no numbers, code or markings to indicate if it is untwisted, twisted pair, cat-3, etc. For wireless coverage to the rest of the house, I need to move the RG across the room. To do this I need a 25 foot cable to run along the baseboards. The question is: what kind of cable do I need? Can I buy a simple silver satin cable from Wal-Mart? Or do I need to find something a bit better? Thanks!