I take a multi vitamin with folic acid and am lucky enough not to be a smoker. However things don't sound too bad for you are you mention that you are only a 'social smoker'. Hopefully you will have enough determination to give up altogether, perhaps before your little miracle happens as it will make it easier for you in the long run.
As for eating healthier, do you want to just eat healthier foods or do you want to loose weight. If you want to loose weight then perhaps you could consider joining Weight Watchers or another slimming club which will help you learn all about healthier options. Otherwise, I recommend cutting out the rubbish such as sweets, crisps and take aways and replacing with more fruit, fibre and vegetables. There's loads of advice on the internet too for healthy eating plans.
Best of luck and some

for your journey.