You could use tokenat and left expression but I don't know if it would be the best option since it will run every tick.
example(if your timer is a number, use str to convert to string):
tokenat(timer, 0, ",")&","&lef((tokenat(timer,1,","), 2)
The first tokenat should retrieve the integer numbers and the second should get two numbers after the comma
Example: timer = 4,37079798734234
Would return 4,37
I didn't tested it on c2 but should work.
Edit: How are you doing this timer?
I think it would be an option doing this way too.
Every 0.01 seconds > add 0.01 to timer (timer as a number)
This way you don't need to do anything and never would return more than 2 numbers after the comma.