For the last couple of years, the U.S. dollar has gotten hammered along with housing prices. Of course there was a housing bubble that was created by the loose monetary policy of the Greenspan era at the Fed. The short-term could bring more downward pressure on both housing and the U.S. dollar, but the trend is unlikely to continue for long.
It doesn't make sense long-term to have a weakening dollar along with falling prices in housing. Eventually the dollar will get low enough that buying property in the U.S. will be a complete bargain, especially for foreigners.
Let's say that as of today the U.S. dollar and the Canadian dollar are at par. In other words, one U.S. dollar can be traded for one Canadian dollar (this is pretty close to reality right now). Let's also say that the average U.S. house costs $200,000. Now let's take an extreme example and say that over the next couple of years the average U.S. house drops to $100,000 and the Canadian dollar rises to $2.00 against the U.S. dollar. In other words, one Canadian dollar will then give you 2 U.S. dollars. It would then cost a Canadian just $50,000 to buy a house in the U.S., whereas before it cost $200,000. You would see Canadians trading in their dollars for U.S. currency and buying U.S. property like crazy. This would either drive up housing prices or drive up the U.S. dollar, or both.
We have seen a crash in the U.S. dollar and drop in housing prices at the same time due to some unique circumstances. The U.S. dollar is the main currency of the world and foreigners are starting to realize that they shouldn't have so much holdings of U.S. currency. And although housing prices have dropped, they are still much higher than 5 years ago and the drop can be attributed to the housing bubble created by the Fed.
It is possible that the Federal Reserve could have a tight monetary policy (which it actually does right now) and see other central banks have an even tighter monetary policy. But this is highly unlikely in the long-term. Therefore, it is also highly unlikely that both the U.S. dollar and housing prices will continue to drop in the long-term. Nobody knows for sure what the Fed will do, but if history means anything, the Fed will most likely start inflating again and we will see housing prices pick back up in a couple of years.