Hi folks I wanted to get fellow artists opinions and help concerning commissioned work. I am not sure exactly if this is the right forum but I really need some input from fellow artist like you.

Here is the situation. I have been asked by a museum to provide all the files I used to create a virtual roman domus (home) located on my website so they can use in an exihibition for their museum. They are asking me how much money I will charge for them to use my work, (my files). From these files they will create create various types of multiple interactive formats, which could include a 3D walkthrough, QuickTime, Flash and the museums webpage.  

I have done some paid jobs before but nothing like this. I have absolutely no idea how much to charge.  I know I worked for about 3-4 months on this project over the course of weekends, nights ,so on , like you all do. I estimate I worked somewhere around 40 - 60 hours on it altogether.

Any advice or info regarding standard rates ,(what to charge) would be a big help. Because I have no clue. :)
Thanks in advance!!