Steering Wheel Vibration

Ok I want to be detailed so I am sorry if this is long...

I have a 1999 Grand Am GT Coupe..Black of course anyways I bought the car used. Everything was cool, but one day I decide to go to Kal tire and get my Tires Balanced and rotated. Ever since then, I have had this nasty Steering Wheel / Floor vibration around 120 KPH. But the funny thing is the vibration would come, and then go. It seemed to depend on the road surface. I went to Alberta Wheel Repair and they said I had 2 Wheels that were Bent. ok great, I get my wheels re-rounded. I take my baby out for a run and bam, I get about 50% of the vibrations I had around 130 kph now.. so my question is...

Now that my Wheels are re-rounded, do I need to get them re-balanced again because of the wheel change? has anyone else had a similar problem and been able to solve it?

O, and btw I took my car up to 210 KPH and the vibration doesnt get worse that much, but its there now after 130 KPH and its driving me nuts!!!

I read on other forums that the Rubber may have buldges and I may just need to buy new tires?

My thanks,
Mortalsin

just an update..I was thinking that the road surface had alot to do with vibrations. Since I got my wheels re-rounded the vibrations were almost gone, but some still there...The highway I travel everyday to and from work is some what worn in places...

so I went out to find a long stretch of paved less used road..I found it and Cranked it up to 180 kph for about 5 min... there was almost no vibration at all except when I hit the break, but at that speeds you are bound to get break vibration.

So I think my main problem was my wheels needed re-rounding.. and the secondary problem was the somewhat rough road surface in places..that would explain the on and off vibrations.