I was trying to get an idea and maybe somone else has had the same problem cause it can be a number of things

 

Under what conditions does the car shimmy? Braking, accelleration, turning, etc? Assuming you feel it through the steering wheel?

Yup, could be many things. Help us with a good description and we can help you diagnose it

 

sorry to bump in but my car also gets very light shimmy at speeds around 100 km/h and over, it doesnt get too bad, it also shimmy's when i brake but its just the brake pedal mostly. my car was making loud grinding noises ( i thought it sounded like an old wooden boat creaking) it also feels a bit loose going over rough dirt roads

 

thats only when turning, but i basically only heard it going over bumpy turns or when my car was parked and i turned the wheel at high speeds i didnt notice it

 

The grinding noises and vibrations during braking are probably due to worn brake pads and warped rotors. A proper brake repair involves replacing these parts and should cure those problems.
"looseness" is a bit vague but could be worn ball joints or worn shocks/struts. Not surprising in a 13 year-old car.