I figured I'd post this just in case. No pics but should be easy enough to follow without them.
Go to your local gas station and ask them if you can have the wiper blades they have replaced. They will probably let you go through the garbage and pull them out.
Once you have one:
1)bend back the clips on the ends and pull out the metal strip.
2) One end should have a notch in it, the other end should be clean and round. Cut a piece off from this end about 4-5 inches in length.
3) If you get some burrs from cutting it off, use sand paper to sand them off until it's smooth again.
4) Using a pair of pliers, hold one end about an inch from the end.
5) Bend this end to form a 90 degree angle.
6) You know have a tension wrench.
7) For added control in tension, you can use two pair of pliers to put a twist in your new wrench so that you will be applying tension using the flat part of the wrench.
8. To do this, about an inch from your 90 degree bend, use one pair of pliers to hold the flat part.
9) While holding the wrench in the pliers, grab the wrench about half inch down from the first pair of pliers with the 2nd pair.
10) Turn both pair of pliers towards each other, until the edge of the tension wrench, is aligned with the flat part of the 90 degree bend.
Steps 7 - 10 are not required, to take a look at this twist, look at my post entitled "First Picks"