the true and permanent fix is however to use the arduino to control a gate driver and use mos fets preferably p channel
try this if you want ive used this a lot http://www.mouser.com/ProductDetail/STMicroelectronics/TD350E/?qs=L6eUzyzWLAvJVVLfLJPI5qS1fNsgAj%2Fl
and this fet is quite robust
http://www.mouser.com/ProductDetail/Fairchild-Semiconductor/FDD6N20TM/?qs=8NSUQxcvzttK7FAUi%252b6Izw%2FkC3V5OVSl