I have a gas furnace and upstairs I removed the old thermostat and it only has a yellow and green wire which the two wire digram it gives me with the digital only uses R1 and w/b . Please help I have no heat.

You can pull a extra wire. Lots of work. Or get a battery operated thermostat.
I can try to look up your thermostat to confirm.
What is the new thermostat name and model number?