Assuming that you're not just pulling our collective chains, there's a Babies R Us conveniently on the subway line at Eglinton and another at Dufferin Mall, both inside Toys R Us. As for Dollar Stores, there's a huge one at Sherbourne and Queen and another going into the Toronto Sun building, apparently. All of these locations will be closer to you and more convenient to transit/parking than Etobicoke or the Port Lands.
http://maps.google.ca/maps?hl=en&um...JAg&sa=X&oi=local_group&ct=image&ved=0CCEQtgM
There are also many and varied independent children's stores all over the frickin' place.
Last, and certainly not least, for the new folks needing to drive to a store from the Port Lands, there's a ginormous Canadian Tire, as well as other big box retail at Leslie and Lake Shore. Given that T&T probably will not be moving any time soon, there's also a great, Asian-centred large grocer already on Cherry.
But... you're pulling my chain, right?