Here's one approach.
To look like a photograph this would have to painted in realistic detail. But what is that level of detail? I looked for the original to find the size, and found to my surprise that you can get this very painting reproduced for $320. Probably you can search and get it done for less too.
http://www.masterpiece-paintings-gallery.com/titian-venus.ht m. If you simply wish to have this gorgeous piece to hang on your wall, perhaps you can have them do the photorealism for you. In this case I would email them about your proposed project and get a quote. These kinds of companies have artist sweat shops in India, etc that make these masterpiece repros, so perhaps it can even be done by the very artist who has painted this exact painting many times. Certainly these repros are painted by highly competent artists.
If you wish to learn photorealistic painting there are many tutorials on the subject
here's a google search
http://tinyurl.com/22z6wf here's a youtube search -
http://tinyurl.com/297sp4 Very interesting stuff. I wish you luck!
Thom