Having your dog sit while other dogs go past is really good - when i'm training my dog to this I take a pile of treats and just distract her while the dogs pass by feeding her, then when they've passed I give her a huge rub-down and cuddle.

If you can, take her for a couple of walks without the pram, so you have both hands free, and keep a small treat in your left hand while you're walking - she'll soon get in the habit of sniffing your hand as you walk.

good luck

(oh, and the people with dogs on loose leads annoy me too!!)