now I'll try an discuss issues you are having 1 I see no gain on the opamps and your running resistance on them. That would mean less then unity gain being sent through. You need to amplify your signal at least greater then the resistance on the inputs. Your 470uf filter caps are to large I'd bring that down to around 220uf which is almost double what you need really. lot of this I cant make out the values. but your impedance looks off as well you want the impedance to be 10x or more lower then the input at the wiper.
the power supply needs to be more then just 2 batteries cause they drain unevenly which causes dc offset.
you should really use a opamp buffered virtual ground something like this is fine but I'd use a opamp with higher drive current
or you could do this in a dip 8
you can read more about virtual ground circuits here http://tangentsoft.net/elec/vgrounds.html