try using buelean expressions just like a search engine:

for example:

searching for "star wars jedi knight game for mac" I would enter something like this: star wars*.dmg

Use "star wars*" and LW will search for files containing "star wars..." ... meaning any spelling after that. The next character after that will match other files that end with the same extension. Since ".dmg" is a OSX disk image and most big files for OSX are shared this way, then you could assume that this file is going to end this way. You can also try ".sit" or ".img"