sql pad zeros left and right at the same time?

Question

I have a bunch of dollar amounts in a varchar field which should be 8 characters long every time, to the format of 00000.00

For example, I have

3495
12.7
-.38
-324.81

which needs to be

03495.00
00012.70
-0000.38
-0324.81

Can this be done in a single update?