I second gardening, DD loves to 'help', we are getting her a little gardening set with a wheelbarrow, rake, spade etc from argos for her birthday.
Also painting/drawing on a blackboard? You can get a blackboard/easel from ikea for £15, they are really good. And DD loves aquadraw, and I love it cos there's no mess!
As for crafts you shoud give it a go - I don't do much painting cos it's too much effort to clean up afterwards, but I use things like cut out shapes, different texture paper, googly eyes/feathers etc (really cheap in shops like Wilkinsons) and DD will stick things on paper and make collages for ages!
Does she like duplo/megablocks? Sorry if that's a bit obvious.
Otherwise why not try and find some new toddler groups to go to? Also, keep an eye out for your next NCT nearly new sale, I went to one at the weekend and got loads of new toddler toys for really cheap, eg a good old fashioned mr potato head that kept her entertained for ages!