First of all, you don't need to run everyday. Second, you need to run more than 4 miles at one time in order to do the 26.2 miles. Our training program just had their long run this weekend of 20 miles. You must incorporate a long run, which will build in distance and time, in your training program and you must incorporate rest days as well.
Go to your local running store (not a chain store) and find out if they have training programs / clubs in your area.