I'd recommend getting in touch with the people at Black Blitz. They are in KW and their customer service is exceptional. They could also let you know what fields are in the area.
Don't choose a gun based upon what feet per second it shoots. Basically every gun can shoot 375-400fps, and most will come shooting in the 400fps range. I highly recommend getting a gun with a true quick change spring system.
Then you can easily change your spring so you can go from CQB to regular outdoor play.
I also don't recommend a starter gun because it's just going to be money lost when you want to get the gun you really want. Arcturus is a brand name that's really affordable for what you get. If Black Blitz doesn't have stock, Gear Up airsoft in Toronto likely does. I definitely recommend Black Blitz for you though because they are in your town!
Edit: Also, using heavier BBs won't help because most fields don't care about your fps, but rather what joules your gun is shooting at. A gun that fires 400fps with .2g BBs is the same joules as a gun firing 328fps with .3g BBs. Here's a chart for reference - https://www.airsoftmaster.com/produc...-fps-chart.gif