How can I get Timer 1 to overflow every 5 seconds

[revelator]

I need a timer to increment and overflow (interrupt) say every 5 seconds but only when when a pin is detected as high (say current is detected). If I use Timer1 on the 16F876, with the maximum prescale allowed of 8 and running at 20 Mhz that would be:

4 * 0.05 usec * 8 *(65535-0) = ~0.104856 seconds

How can I get Timer 1 to interrupt at longer timed intervals say 5 to 10 seconds?

Can I use Timer0 as another prescaler to Timer1? What is the common method for longer timed intervals using timers?

thanks in advance