Diet for long distance running..??

Licratonic

I have a question about how I should be eating if I would like to perform better at running. I'm planning to do my first half marathon in November this year. So now while I'm training (I'm still in the beginning fase - only running 3 - 5km 4-5 times a week, but going to start slowly increasing that - I've appointed my hubby as my coach, he's got a few half marathons under the belt, so he'll coach me on the running bit, BUT what should my diet be? I can't really rely on him telling me what to eat, cos firstly I think diets differ between men and woman, also, his distance running is way more than mine...so I don't really trust his judgement with that...I've read that carbs are your best friend while doing long distance running, I'm running in the evenings...can someone shed more light on this? Some examples of a diet plan would be great!