I would express enough for one bottle feed per day and keep doing morning / night in the mean time .... by 12 months they only need two milk feeds so even if you can get til then you can then introduce cows milk to replace one of the BF's if you need to, or just keep going with the morning / night thing and gradually swop over.
Cows milk is harder on the digestive system than formula, and doesn't have all the other added vits / mins in the correct level that a bubba needs, so I would hold off on the cows milk if you can. Maybe try another formula? If you're using a gold one then switching to a non-gold (they taste a bit better) might help. Otherwise I would just leave hubby or nana at home with him and a bottle one day and see if he will take it if you are gone for a few hours.
Edited to add: It sounds like you are doing 4-5 BF's a day - first thing I would do is try to drop down to 3 slowly, so that there is only one you need to worry about while at work .... hopefully he will take a formula bottle by then, but if not an expressed bottle or a sippy cup of formula with a tiny bit of milo might get drunk! But he will only be a few weeks off 12 months then, so not the end of the world if they whole 3rd milk feed isn't consumed, as food is more important by that stage and at 12 months he should go down to 2 milk feeds anyway.
Edited by Nikki - 08 January 2013 at 8:06pm