licensing/distribution of DLL's question

I wrote a postgres embedded application that uses libpq and requires the postgres DLL's in the bin directory to run. I am curious if I am allowed to package my app with the DLL's without distributing the entire postgres database application, though I could include all of postgres.

postgres is under a different license than my app. my app is under the GPL3 license. Since I wrote it, I can always change it. (it just got practically finished)

also, I am curious - if I include those DLL's and somebody has a newer version of postgres, will the program still run against the database, or will a fresh set of DLL's have to be copied out from the bin dir again?

Jim Michaels <jmichae3(at)yahoo(dot)com>