Hi smiling - I'm sorry that bfing directly hasn't worked out for you, do you know why? Have you got any support from a bfing counsellor/IBCLC/Infant Feeding Co-ordinator to help with the EPing?
Tricks for increasing pump yields include:-
Massaging the breast towards the nipple before pumping,
Listening to relaxation tracks while pumping,
Breast compressions during pumping,
Hand expressing after pumping,
Double pumping (pumping both sides at the same time),
Looking at or holding baby or thinking of baby while pumping,
Checking the breast shield (the bit the goes over your nipple) fits well - a poorly fitting shield can not only inhibit the amount of milk you pump but it can also damage your nipples and cause pain - Medela, Ameda and Ardo all do sized breast shields (there may be other brands that do as well but I am not aware of them),
Block pumping - double pumping for 10 mins, then resting (reading a book/watching TV/having a shower/whatever you fancy) for 10 mins, then double pumping for 10 mins, then resting (or whatever), then double pumping for 10 mins (if you have a single you swap sides after pumping for 10 mins). This won't increase the yield at that pumping session but rather like cluster feeding from a baby work to increase yield in the future,
Covering the pumps so you can't see them with a muslin or under your top as it's been noted that looking at the milk coming out can inhibit the amount you pump (probably something to do with increasing stress levels).
A double electric pump is probably your best bet as you can be hands free and it can halve the time you spend pumping. There are some good pumps on the market and you can hire hospital grade double pumps too (check your local bfing group or Surestart children's centre as some hire them out for free or a low fee). The only caution with Medela pumps is that they have an open pump motor so milk has been known to be sucked down the tubes and into the motor where it can't be cleaned and mould grows which could potentially contaminate future milk that's pumped. Ardo and Ameda have closed pump motors (this also means they are safe to buy and sell 2nd hand as you can just buy new breast shields and tubing if you wish).
You can also get special pumping tops/bras for hands free pumping or you can cut small holes in a tight vest top to feed the breast shields through or even just clip your bra back up.
Have you seen this or this on bottle feeding? They have loads of good tips on how to maintain the closeness of bfing while bottlefeeding and how to feed responsively which I am sure you are but it's good to give it to others who might feed the baby
. This has details on how to work out how much milk your baby needs a day.
Have you considered a Supplementary Nursing System or Lactaid to encourage baby back to bfing? They work by increasing the amount of milk the baby gets while bfing which can help a baby who prefers a bottle. Sorry if this is something you have already tried
just thought it might be worth mentioning.
HTH