I've not been able to get any gold when i sell items to her. Is there an issue with selling stuff to her after i've trained archery with her.

If you're talking about Sorine Jurard from Dawnguard, then I've had that problem too. I use Aela to train me in the archery skill instead, in order to avoid this glitch. I noticed this is also listed as a bug on the UESPWiki: http://www.uesp.net/wiki/Skyrim:Sorine_Jurard

That svcks, there's probably a way around it. I'll try waiting a few days if that doesn't work then i'll try to pickpocket the gold, otherwise i'll just have to use her for buying more steel and dwarven bolts.