Drifting Left

Drifting Left

Heres something strange, hope you all could help me with this.

When I have my Steering wheel Perfectly straight, as in the Toyota Emblem on the Steering wheel is centered and the top of the logo is pointing up. my car will Drift to the left, really quick to, like im changing lanes. But when I have the Steering will turned to the Right a little bit, meaning the top of the Toyota emblem is pointing to the Right. the car goes straight. When I left go of the Wheel and the Power steering centers the wheel, it starts drifting again to the left. I took it to Toyota to get it checked out, and they said they checked every Suspension part and said that nothing was loose or bent. I had them do an Alignment and that still didn't help. They told me it was my Tires. I got my Tires and Rims at Les Shwab which are 17, I think its like 205/40/17. I think thats right. But Les Shwab says my tires look fine. One thing I do notice is that the Car in the rear bottoms out quite often, and they even did that on Stock Rims. Does anyone have any Suggestions for me? I'm going back into Toyota on Wednesday of Next week to have them look at it again. Any help would be greatly appreciated, as my girlfriend drives the car to, and I feel this to be a safety issue.

|-Goku-|

I actually have hit a curb, pretty hard actually. ya I figured my struts where out. so I will get those replaced. How do I straighten the wheel also? Thanks for the quick replies