If medical attention is out of the question, then NightHiker, along with OBG's suggestion of a Sawyer extraction kit is what I would do. The Sawyer kit is said to be able to drain up to 50% of the venom injected, assuming you can kill the snake and get it into use within the first couple of miniutes. Not something to rely on IF medical care/anti-venom is an option. If however medical care is NOT an option, it is better than nothing. Every little bit of venom drained is less venom in your body, and the psycological calming effect of having done somthing other than panic will help keep (or should help) your heart rate down....... Just my 2¢ Good luck on your journey.
-Bill Liptak