couple of questions

I have a couple of questions about the new mac book pro I got. I have worked with macs before but only in school for graphic design reasons, so I did not get too much in depth experience on them. Here are a couple of the questions I have:

1. Everytime I want to watch anime on my MBP, I have to find the .dmg file for VLC and then click on the .omg file to watch my anime, even though the .omg files are set to default open in VLC. Is there a way I can set it to just click the .omg file without having to first click the .dmg file to start my movies?

2. I bought this computer for gaming mainly, however a few of my games are wondows only games. One example is Titan Quest Immortal Throne. I got a freeware version of a parallel software. I want to parallel install Windows XP for the games I can't play on my mac. However when I start to Install the software it asks how much ram I want to allocate to XP and how much hard drive space. I have 4gb ram and 250gb hard drive space. Titan quest's reccomended settings are 1 gb ram and around 10 gb hard drive space. What would be an optimum setting to be able to play titan quest on this software and still have good performance.

Those are the only questions I have now. Feel free to answer them in AIM, MSN, or YAHOO. Much faster that way!