Wow! That's cheap.
I would opt for somewhere in the town centre on one of the clifftops. You'll be right by the beach and near the town for shops/restaurants/cinemas too.
Right on the seafront there's the Oceanarium, there's a Wacky Warehouse soft play. There's a landtrain that goes along the seafront in two different directions.
You could do a boat trip to the Isle of Wight or Poole Quay or Swanage.
There's the Bournemouth Eye which is a tethered air balloon.
There's Bournemouth Gardens and often lots of activities arranged in there for holiday makers.
There's the BIC, Pavilion Theatre and Pier Theatre for shows. Or 2 cinemas.
There's an open top bus that goes along the coast road to Hengistbury head where there are lovely walks and a little train.
Get the bus to Poole and Poole Park, where there are ducks, swings etc, a train (prob too young for your dd) but there is ice skating there.
Honestly there is tons to do!