Car moves right side

I have Mitubishi galant 1998 model, have done 304000, recently I did wheel balancing and tyre swaping because it was vibrating a lot when it reaches the spped of 70 miles/hour. I also changed teh front break pads at the same time at a garage, after that while driving, my car moves to right side, I literaly have to hold the steering otherwise car will go completely n the right side. More over vibration is still there and more so at idle. Kindly suggest a remedy. I will be thankfull to you.

regards