Home Depot of all places stocks many sizes of glass fuses(like used in our DVDRs) they even sell the slow blow type, they are in the electrical dept. in plastic flip down cubbies. Of course Radio Shack also stocks similar fuses. Always replace a fast acting with another fast acting or slow blow with another slow blow, using a fast acting in place of a slow blow won't really hurt anything but it will be more prone to blow with surges.
Bring the fuse with, since fuses come in many sizes that may look similar to each other from memory.