Hello Pankaj,
So basically will be a Active/Standby scenario pointing to an outside router that will perform load balancing.
You will need to focus on the ASA active/Standby configuration.
here you go:
http://www.cisco.com/en/US/products/hw/vpndevc/ps2030/products_configuration_example09186a00807dac5f.shtml
Any other question..Sure..Just remember to rate all of my posts
Julio
Julio Carvajal
Senior Network Security and Core Specialist
CCIE #42930, 2xCCNP, JNCIP-SEC