That was one of the "marketing points" for the ISS, that it could serve as a waystation for Moon/Mars bound astronauts.
I haven't seen any mention of stops at the ISS to resupply Orion CEV lunar missions in the 2020-2024 time frame. Up to now, all visits to the ISS by the U.S. Space Shuttle and Russian Progress ships have been to resupply ISS with consumables and cargo.
"I guess it would make it even more costly if they were to build another space station near the moon, then again, what would be the reason for it."
Interestingly enough, at the 2nd Space Exploration Conference this week, the Russians included a space station in orbit around the Moon and Mars in their long range exploration concept plans 20+ years in the future.