I hope I'm not raining on your parade here...
Some of the early GigaSampler libraries imported well into Kontakt, but they were quickly eclipsed by newer libraries that offered better sounds, more features, etc. There are a handful of libraries (growing smaller every year) for which I have not found replacements, and for which I have not found a suitable player, but I can sadly tell you that importing Garritan Orchestral Strings, Larry Seyer's Acoustic Bass, or any of the Scarbee basses does not work well. My guess is all three used many of the advanced features of GS3, and they don't import into Kontakt cleanly.
There are two other players, G-Player and Samplelord, which look really promising. I haven't invested in either one yet because I'm waiting for them to properly import my favorite libraries. And they do get closer with each release - in fact G-Player is not (I believe) importing at all, they are playing the native files, just not quite as I remember them<G>!
Don't give up hope!