you need a step down

[dagakshay]

you need a step down transromer for 2.5A….

and refer to link:

http://www.engineersgarage.com/electronic-circuits/variable-power-supply

http://www.engineersgarage.com/electronic-circuits/fixed-voltage-power-supply

 

and atke T0-3 packaging of 7805 what might provide you the higher o/p current at constant voltage