Agree with Mike. Unfortunately, it looks like whoever sold you the anemone really doesn't care about it or you - just making a fast buck I bet. Anemones really do need strong lighting (they are photosynthetic), a mature tank (9 months plus) and some are near impossible to keep in an aquarium - although saddly, shops keep importing and selling them. There are some that are great in aquariums, but again, you really do need better lights to keep one. I'd take it back if an upgrade to the lights is not possible within the next week or so (it'll die if not, and pollute your tank).
What tank do you have? Do you have any other livestock?