Hey, I live in Mississauga and was disappointed when Silver Tip closed down; my dad told me he'd been playing there for years.
Two places I go with my friends are Captain's Snooker Club, which is in the plaza at Tomken and Dundas, and Big Slick, which is at the corner of Queen street and Britania (Streetsville).
I find that pool at Slicks is overpriced but they have some great jitz tables there and the atmosphere is often really lively. Captains is much more reasonably priced and (though don't quote me on this) I think they recently re-felted some of their tables. They have both pool tables and snooker tables there!
If you find a new place, let me know