I agree with the last posts concerning shoes. I found a store that did the gait analysis and what a difference the right shoe makes! Do this as soon as you can so you don't develop injuries as you increase your mileage. There are plenty of plans out there that you can use to get ready - 8 months is plenty if you just want to finish and you stick with it.
As far as the weight lifing thing goes - I lifted 3 days a week prior to getting into my marathon training plan then did no weight lifting. About 4 months into training and 2 months from the race I started having all sorts of knee and IT band issues. I went back to the weights and worked on my quads and hamstrings as well as my adductors and abductors. 3 sets at about 12-15 reps. This helped considerably. I also did some very light upper body stuff but mostly concentrated on stretching - very important.