I may have some solutions, but they require a little more knowledge. When you say you’re computer cannot handle it, are you talking about its processing power or the amount of drive space available?
If you are having issues with drivespace for exporting your final copy, try networking your 2 computers together and exporting the final version from one to the other. It may take a mind numbing amount of time, but it will solve the drive space issue. However, I would note on this that means you probably won’t be able to do a full preview of it before you render it out. You will unfortunately have to review it after the LONG export. Alternatively, if you have an external hard drive this may be a better solution. Import the footage (or transfer it) to the external drive, then set up your computer’s main drive as the render drive. You may detect some audio video glitches over firewire 400 or 800 when you play it back, but when you render the video and audio, the new files will be written to your computer and those should go away, if they don’t, don’t worry, they won’t exist in the final rendered out version.
If you are having issues with computer performance and speed there is another possible solution. When you say you have 45 minutes of footage do you mean in 1 large file in your editing bin or as a collection of many files? If it is one large file, try importing it in smaller chunks and splicing them together, this helps final cut by breaking up the file sizes and helping manage the read write procedure. If you have many small files that are causing issues try rendering your project into a couple larger chunks and then bringing them together to render the larger piece. The computers sometimes have issues when there is a lot of editing on large projects, so by exporting to fully rendered pieces and splicing them back together the computer has to do less work to put the full piece together.
Hope one of those solutions helps you.