Fluid intake is definitely a factor - you need to ensure that you're taking in enough fluids to produce the volume of milk that you need. You don't want to drink a ridiculous amount (recent studies have shown that too much water can actually decrease milk production by altering electrolyte levels in mom) but I would get 8 glasses per day at a minimum, and more like 10 if you can. Keep in mind too that any milk, juice, etc that you drink would contribute to your fluid intake, but that coffee, soda, etc. will not as they contain caffeine, which is a diuretic.
As for pumping vs. nursing, that's a personal decision with pros and cons for both. Nothing stimulates milk production like baby actually nursing - so if you could take a nursing 'holiday' (spend a weekend nursing on demand, lots of skin to skin, etc.) that could do wonders for your milk production. More frequent nursing day to day can be very helpful too. BUT... Frequent nursing alters your EASY routine, and it's easy to fall into a feed-to-sleep or snacking habit. As long as you're aware of it, it tends not to be a big deal though - for example, fitting in extra feeds by doing EAEAS, rather than EAES and feeding to sleep.
Additional pumping sessions will stimulate your milk supply while allowing you to maintain your routine, but pumping is not as effective at increasing supply as nursing. There are hormonal things that happen between mom and baby that just don't happen between mom and pump.
HTH!