I would call the hotel directly and be persistent. They may come up with a better deal--but in my experience, the savings haven't been hugely different than the posted website rates.
However, take into account the perks you get at this particular property, and then figure them into your overall trip cost:
--a satisfying free breakfast (with fresh fruit that you can take for later)
--a refrigerator (and in some rooms, a microwave) that can be used to store/prepare lunches/light dinners. There's a 7-11 next door if you want to buy milk, frozen foods, etc.
--COMFY beds where you'll get a good night's sleep
--a FREE shuttle to the parks every half hour, even though it's an easy walk away.
--free parking, and plenty of it (rare around
Disneyland!)
Sometimes those differences can even out a cheaper hotel with fewer amenities.