i purchased it so that i can access the trolls but, i would also want to be able to use all of the races i have paid for and not just the trolls and the base races. i have the first expansion.

Sadly the way is having bought the series on Steam. Apparently the game doesn't recognize other games purchased on GOG, and neither GOG nor the developers seem to be in any particular hurry to fix this. See this thread for more info:

https://www.gog.com/forum/spellforce_series/spellforce_3_fallen_god_not_registering_previous_games/page1

it does not help me, because my laptop is too weak to handle steam and the game at the same time.