This sounds like two problems. The low speed vibration sounds like an imminent tire failure. The steering wheel off center can be both the tire and/or misalignment. Have the front end and tires checked asap.
RepairPal Certified shops can diagnose and repair your 2003 Mitsubishi Galant. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.
Should I change the front tires or do wheel alignment?