This circuit flashes the LED about twice a second. I changed the capacitor to 100uF and now it flashes once every 5 seconds. What do I need to change it to so it flashes roughly once every 60 seconds? Thanks.

 

Proportionality should work. You increased the capacitance by 10 and slowed the flash by a factor of 10. You want to alter the origianal by a factor of 120. Try 1200 uF.

 

Is that an astable multivibrator?

How I wish someone taught me in my EE classes how one of these babies works. Its always boring circuits that do nothing or very little. Meh...

It looks so simple, but its not right?

 

Well, the trouble with increasing the size of the capacitor is that peak current through the LED will skyrocket.

The cap charges up until the NPN transistor kicks on, which turns the PNP transistor on dumping current through the LED. The larger the cap, the more current gets dumped.

Time to change over to something like a 555 timer.
[eta]
Have a look at Bill Marsden's blogs:
LEDs, 555s, Flashers, and Light Chasers

 

The 555 is my next step if this doesnt work out. The reason I am trying to get this to work is that I have a 4.5v voltage that I need to stick to. The 555 needs around 9V.

 

Look at using CMOS 555's.