I had plantar fasciitis for two years so I know exactly where you're coming from! The catch-22 of the situation is that to improve the PF doctors say you need to lose weight, but to lose weight you need to exercise which can be impossible with PF. It's taken me ages to get back into exercise as a result.
I can now jog 5km without any foot pain but it took a lot of work and I wouldn't recommend trying it until you get closer to goal weight. In fact I wonder if you're pushing things too early by jogging on the treadmill. Could you stick to walking or other activities until your feet are mostly healed?
Here's the combination of things that I found useful in treating my PF:
- Fit-Flops (http://www.thefitflop.com.au/
). I rarely get PF pain since I began wearing these. They have ample cushioning, arch support and the design actually works the muscles of the foot, strengthening the plantar fascia rather than letting it rest. MBTs are supposed to work the same way but they're much more expensive so I haven't picked up a pair yet. Crocs are also supposed to be pretty good in this regard, though I picked up a pair of their 'Alice' style shoes and they're not as well cushioned as my Fit-Flops. The best thing about Fit-Flops is that they work your leg muscles while you are walking. So not only is walking more comfortable it's more productive making it a perfect exercise while your feet are recovering.
- Stretching the plantar fascia. If you click on the 'show transcript' link on the following ABC Radio National news article you'll find a description of this particular stretch. http://www.abc.net.au/rn/healthreport/s ... 784908.htm
- Elliptical trainer. From the sounds of things your achilles doesn't like this machine though. What about a stationary bike instead? If you use the balls of your feet on the pedals it shouldn't put any strain on the plantar fascia.
Good luck! If nothing else you could always try a pedal exerciser (http://www.oo.com.au/Pedal_Exerciser_P6083C0.cfm
). Apparently they're used quite a bit in physical rehabilitation so they should be quite gentle on your feet. You can also use them to exercise your arms.