well the good thing is that your PIC12F683 has a PWM feature. so based on that...

your best bet is to review this page referring to IR Communication.. as it explains a lot about the registers you need to set up.

the tricky part here is setting your Duty cycle. assuming a 1:1 prescale

(4Mhz / 4 x TMR2 prescale x 325) - 1
(4Mhz / 4 x 1 x 325) -1
( 4,000,000/1300 ) - 1 = 3075 (3.075 ms)

Not sure you can load 3075 into PR2 register...