What is the voltage you are giving to L293D and the 2 motors? How long do you want to run the motors? How much current does each motors draw? Are you going to charge the battery without removing it from the circuit?
The battery can only give 1.3A continuously for 1 hour. If one motor draws 1A to run then the motor runs for 1.3 hrs. The battery is 7.4V and your motor is 12V. Are you sure your motor runs from 7.4V?