If the build process times out it's usually due to huge source files that result from models with a large number of switches. As Kris and Bryan pointed out, try to reduce the number of switches and use the power modules wherever possible.
Even if the model can be compiled, it usually results in large execution times if the source files are that big. If you absolutely feel you want to try anyway you can increase the build timeout in the file 'info.xml' in the Target Support Pacakge installation directory. Find the line starting with <Timeout> for your respective target (there is one for RT Box 1, 2 and 3 respectively) and increase the value. You should be prepared to run into other problems though.