Using TMR1 and the PIC main oscillator at 4MHz is impossible to have 60s counting, because the maximum prescaler is 8 (clock division). At 4MHz and prescaler = 8, TMR1 will overflow every 524288 us or aproximattely every 0,5s, as follows:
65536 x 1/fosc/4 x 8 prescaler
65536 x 1us x 8 = 524288 us
If you use a 32768Hz in the TMR1 external oscillator, you can obtain 16 s counting (steps of 244.141 us)
You can configure TMR1 (with 32768 Hz xtal) to overflow every 15 s, make the interrupt and increment a variable. When such variable reaches 4, you have your 60 s timing (and clear the variable after this).
Another idea is using a low frequency clock feeding the TMR1 input, lets say 1000Hz. This way you get 60 s when TMR1 reachs 60000.
If u want an accurate delay for any application do as rkodaira said, but if u intend to make a clock use 4MHz Xtal and /8 prescaler then u can subtract the error every while.
Hope that this this is what u r asking for and that i've helped u