Hi @tailinks,
@crazydaze and @underground is absolutely right, you need 500SP.
Or you can check out my app which is designed to give you the ability to vote with desired power.
You can vote on posts only at the moment because you'll need the link to the post.
...Well, you can vote on comments too but it is a little challenging:)
Check out my app promoting post if you like: Minnow-Power
If you have any questions, just let me know:)