LM4702:increase the output current,possible??

You could try a different National part, LME49810 has 50mA of drive current, LME49811 is a mono version of the LM4702 and has like twice as much drive current as LM4702. LME49830 has similar drive current as the LME49810 but is lacking the Baker Clamp and is targeted more to FETs (16V possible bias). See which one you want to try before spending too much time on another. The advantage of the LME49810, 811 and 830 is that one board can be made for all three.

-SL