if it really was you who put the password the best piece of hardware you can use right now is your brain

relax and try to recreate the whole scenario, time, place, mindset of when you were leaning on the bitcoin client, then put your hands on the keyboard, focus and start trying

hopefully the password will emerge

source: my own experience, I have set up a password on a 50 btc worth wallet. This is how it happened:

It was late night in a hostel, the only computer avaiable, not only a public a PC but I had to use standing up, and, to increase the anxiety level, I was drinking beer. Put the password and shutdown the PC. Then I left the place I was for three days, here is where I needed the password and: WTF?! Wrong password! Don't panic.  At this time the password only existed on my brain, then just said to myself I was going to remeber. I did exactly as I told you above. Took me one day to go back to the place I had set up the password. And two more days acting like "12:01" movie to finally extract it from my mind. The pass was a 12 chars long phrase.

Hope this inspires you.