Runner's Training Tips: Injury management

I'm having a hard time figuring out by how much, if at all, I should reduce my milage due to foot pain. Do I stop altogher? Just reduce the miles? Keep my schedule until physically unable? I'm building my base for a marathon May, 2008, so have plenty of time, but don't want to mess with my schedule. Currently @25-30/ week, with 3 up, then 1 recovery, around 12-15 miles. I have tenderness and minor swelling on the top of one foot by the bone/tendon that leads from the big toe to the ankle. Have not been to the doctor (They just tell you to stop running-duh!). My foot normally does not hurt while running, although I can "feel" it. Some minor pain next day. Had major pain about 6-8 weeks ago, so I dramatically reduced miles, which solved the issue, but now that I'm increasing, it has returned. I'm on a rolll & don't want to stop!