Please Advice

Hi,

I am a H1B holder working in Detroit and I became a landed immigrant in April 2008. I took my landing by driving from Detroit to Windsor, Canada on car. I only stayed in Canada for a week but got my PR in a month's time as it was mailed to my friends address.

After April 2008 I never went back to Canada as I was hopeful that I will get my US Green Card but that seems to be out of question for now. Now I plan to make short visits to Canada may be to find some business opportunity so that I can buy a business and move to Canada.

My question is can I travel to Canada in my Car without having any immigration issue as when I landed last year I was asked to transfer both my cars to Canada and also change my Driving License from US to Canadian. Since I never went back I did neither. Will I have any problem if I drive my car to Canada with US number plates and US driving license.

Secondly, while landing I had provided a list of my personal and household items that I would be taking tax free to Canada, which was stamped by the immigration officers as an approval. My Question is how long I have until those documents become unacceptable in the border crossing and will my personal items be taxed since I did not move there immediately.

Thanks.