Hibiscus need direct sunlight, so start to acclimate it to that. After a few weeks, you should have it living in a spot with as many hours of direct sunlight as possible.
Also, just so you know, what you have is a Hibiscus rosa-sinensis, which can be grown as a tree or shrub, it just depends on how they were trimmed.
Many times, even with direct sunlight and enough watering, hibiscus will wilt because they're pot bound. Check yours and if this is the case, pot it up or if you don't want it in a bigger pot, you can root trim it.
To do this, take it out of the pot (duh!), and trim back the smaller roots 1"-2"'s. You will see larger tap roots; I don't trim those, perhaps someone else here does and can advise you on this.
There's a description and photos of this here: http://www.rozpat.net/Basics%20and%20Beyond.htm
By trimming the branches and the roots, you can keep a hibiscus at a certain size pretty much indefinitely.
Good luck!
Barb
Barb