I don't know if it's too much, I know it's more than rachel had at about this age - she would have 4oz in the morning and 6oz at night and that was it. we had to limit the morning milk because she wouldn't eat her breakfast and then would get over hungry (something she can get to quite easily and is worse than over tired) and we had to remove mid afternoon milk because she wouldn't eat her tea.
as for snack options, here's our list - apple, banana, grapes, pears, melon pieces, raisins, toddler biscuits, home made flapjacks, yoghurt, cheese, popcorn (without any salt or sugar), toast, pitta bread, crumpet etc
hth