If the house is listed, any Realtor in that immediate area should be able to pull the house up on the MLS.
If you have neither a listing number or an address, contact the site's webmaster and ask how to get that information.
However, one additional point: You don't need the lender's information at this point. If you want to deal direct with the owner, that's fine. Do so. The owner can tell you who the lender is.
Hope that helps.