Dear Pramod,
U can as well use ULN2003 if u donot like transistors. They have darlington paired transistors which has higher current ratings.
donot directly connect ur micon pins to the display they may get damaged bcz of more current drawing nature of displays. u can also use 74245/244 a bidirectional / unidirectional buffers.
if the segments are not clearly visible then u can increase the current ( not more than 20/30mA) by removing the resistors between the driver and the displays

good luck.
-sathish