Feed my bugs again? or just add more?

About a year ago we made a lambic base using the Wyeast Lambic blend. About four months ago we added some Rainier Cherries I had frozen last summer to use in this beer, just to experiment. So I pulled a sample last night, and although I am getting a good funky aroma, there is little sourness...the beer is still good, kind of funky, but still with the fruity taste of the Rainier Cherries. I'd like to add a bit of sourness if possible, so as a newbie to lambic brewing this leads me to the question, should I pitch more bugs, if so what would you suggest? And should I feed the bugs again, I was going to maybe throw in some golden raisins that I have for another lambic I am working on..what does everyone think?

Pitching some bottle dregs from a few relatively fresh bottles of gueuze wouldn't be a bad idea. The microbes in lambics, and other commercial sour beers, tend to be more aggressive than those sold by the yeast labs.

What is the current gravity? If it is really low you could feed it.

I'll have to check the gravity, I pulled the sample to do so but........