I agree- sounds like your DD is ready. Both my DS's were about 6 or 7 months I think- just when they were able to sit properly.

We got our seat cover at Big W- was about $40- ours had a little pillow and lots of attachment toys- it converts to a little playmat (not that we've used it for a playmat- cause they were to active to want to sit still on it by the time we got it).

I used it all the time with DS1, but these days with 2 of them I seem to always forget to take it- by the time I get us ready, pack nappy bags for 2, pack snacks, grab them both waters and make our way down to the car- along with my recycle shopping bags- i just don't have enough hands and memory left...lol! Plus now that I've got 2 sitting in the trolley I usually have to try get one of those double sitters- so it wouldn't fit anyway. I wonder if any has designed a double one? Anyone seen one? Or do you just buy 2 bigger ones?