I'm doing my first Marathon in April too!! I think you've been given some great advice and your times are perfectly respectful so I really wouldn't worry too much about that. If at all possible, i would consider joining a club. Even if it means you can only run once a week with them it would be so beneficial for you. I joined a club a couple of months ago and my confidence in my running has really gone up. I know it's hard to fit it all in (I have a 6yr old) but if you could even make the Sunday run with them, I'm sure it would be worth your while.
I would mix a bit of hill and interval work in with your week day runs and get signed up for a half after Christmas. Learning how to pace a run and keeping it slow and steady is the key I think - something I really need to work on too!! As this is my first marathon, I keep saying to myself 'the goal is just to finish it'. I'm really not worried about times and although I would like to run all of it, If I have to walk then I walk. As long as I get to that finishing line!! Already that relieves a huge amount of pressure.
I've had great use out of my Nike+ sportsband but find it annoying having to scroll through to see time, pace etc. I currently run 4 times a week and next year will be running my first half marathon in Feb then the Brighton Marathon in April. Trying to do measured intervals/speed work with the sportsband is very difficult and it has no light so I can't see any info when it's dark.