Ahh I am an expert on this as I have been towed more then I like to admit...
If you been towed and its in inpound, there is no way to get it out now except to pay. no if ands or buts. You can however fight it later and get this back. Or you can try and fight now, car stays till you pay or judge authroizes release.
That being said , are you sure its at the impound, sometimes they bring them around the corner.
you need to call a traffic lawyer (
www.trafficlawyer.com also some links there) you can also call 311 and ask regarding notice, rights, where it is etc
The fine, is 200 for the hook up + 40 in tax + ~30a day storage for any day over the first day (IE it was towed sunday, you getting charged one day storage on Monday) figure to pay close to 300 dollars to get it out.