That will currently not be possible. The way your site looks right now there's a lot unrelated files as there's no link or evidence that the many .wav files are actually related.
Also there has been a policy change, we don't do the unmetered plan anymore, at most we could double the space available (you can ask for double again if it is needed though).
Before we can do anything however we would need to be able to see how those file relates to your site. If they are part of a game as I suspect, there would likely be a limitation to how much space those files are allowed to use up, although ToS currently only speak of flash arcade scripts this may be similar enough to fall under that category as flash arcades aren't really that much used nowdays from what I seen.