You have only 23 items listed at the moment, so I wouldn't worry about it much.
If you try to switch to dotCOM at the moment you will need to reload all your pictures, but you can use a cut and paste for your descriptions.
Any items that are listed on dotCA before May 1st will be grandfathered (left in US dollars) until August, if that helps.
To list on dot COM, just go to the dotCOM site, and list your new items. You could start today.
I usually remember to add a note to my new listings telling me which site this lot is on and the date listed.
However.
Your items are bulky.
Unless you have a method of shipping from the USA, I would reconsider changing over.
Remember that your customers see your items in Search with the currency of the site where they are looking. And with both currencies on the listing itself.
If you stick with dotCA, you can use Calculated Shipping for Canada and the USA (and overseas, but that's usually less important).
On dotCOM you will be forced to use the Flat Rate shipping options only.
A mistake in Flat Rate can be very expensive for you.
So if you list your sewing machine on dotCA, your buyer sees precisely how much shipping will be to his doorstep. With dotCOM, you have to guess at a reasonable average for shipping to Ottawa, Yellowknife, Oahu, Atlanta, or San Diego.
