Skyauction.com has historically had good deals on Rooms on The Beach in Ochi (Ocho Rios)....but you have a larger budget.

Personally I would not suggest my own mother stay in Ochi...Negril beach vendor pressure times 1000.... There are several options lesser found on the internet all around Ochi or at least away from downtown Ochi. In Priory, a couple miles west of town I've rented a 2 bedroom cottage on the ocean for $35or$50 a night. Maybe look closer to Falmouth where you can explore the cockpits(interior of the island), caves, that glowing water stuff outside of Mobay, Ochi if you desire, the Martha Brae river rafting thingy...nice bed and breakfast option over there at Cher's.