The way I'd do it is as follows:
The syntax is from the Turing simulator I link to below. It is
[next transition],[new symbol],[direction]
The actual code:
name: Binary to Unary
Basically move till you've passed two blanks(Step 1), then write a 1(Step 2), move left till you find a blank(Step 3), treat the number to the left as a binary number and subtract one from it(see below for details on how this works)(Step 4), Then repeat steps 1-4 until you can't subtract any more(in my case the subtract routine turns all 0's in the number we've been subtracting from to 1 and then hits a blank), go back turning all ones to blanks till you hit a blank, then go one farther turning that one into a blank.
It turns 101 into 11111
Subtraction routine, start at the far right of the number, if it's 0 change it to one and move left doing the same thing to each digit you come across, if it's one see step 1