If I were heat treating with that forge, here's what I'd do. First, I'd turn the lights down low. Then I'd put on some mood music. Barry White or something would be ideal. Then I'd fire up the forge and adjust the flame down a bit, and then, with the blade held firmly in a pair of tongs place it into the forge. I'd heat the thickest part of the blade first (most likely the ricasso area) and gradually bring the whole blade up to a uniform temperature by moving it back and forth under the flame, being very careful not to overheat the tip. With the low ambient light it's much easier to see the color, and as has been mentioned several times already, good temperature control is very, well,
critical 
Anyway take your time bringing it up to temperature, and watch closely for decalescence (when it looks like shadows are moving across / through the steel). That's your first indication that the steel is austenizing. Check the steel with a magnet, and if it is indeed non magnetic, then you know you're up to temp. Put it back in the forge for a bit and keep it at that temp but don't get it hotter (or brighter!). Remember to keep moving it around and keep the color / temperature uniform. After an adequate soak, quench it in your oil.
You won't be able to achieve as precise or consistent results as you could with better equipment but you will be able to successfully heat treat a blade. As you gain experience you'll be able to judge color more accurately and become more proficient at heat treating. Also be sure to test your blades to make sure they've been heat treated properly, and occasionally test one or two to destruction so you can really dial it in.
Remember, 100 years ago bladesmiths didn't have high grade steels with known alloying elements; they didn't have electric kilns or salt-pots or multi-burner heat-treat forges with digital readout thermometers; they didn't have specially formulated quenching oils... but they did make very good knives. Maybe not incredibly fantastic super high performance knives, but very good knives nonetheless. Remember, good equipment is wonderful to have, but it's no substitute for knowledge and experience.
