Would it be advisable getting and alternate power source (battery of some sort) to power my amp? How would I go about fitting it and making sure it keeps itself charged?
a split charging system. your alternator would charge both. you could put it in the boot, or anywhere really. however, unless you are running some crazy power, you shouldn't need to fit a 2nd battery...
you could always get a power capacitor if your battery cant keep a good enough supply to your amp, a power cap would prob set u back around 100 squid depending upon manufacturer etc