Instead of getting public IP from two seperate ISP, i reccomend that u go in for Regional Internet Registry that allocates IP like APNIC for Asia Pacific region. In doing so ur IP address will not be dependant on one ISP and can failover seemless with correct protocols enabled on ur routers.
The negative part of this is that, u will need to change the existing public IP to new ones and will have to re-do ur DNS entries too.