When you make the call, say, "I think it's a stroke." That lets the 911 dispatcher know to act quickly and get an ambulance to you right away.
While you wait, the best thing you can do is sit tight. As the minutes tick by, new symptoms may set in. Still, you're much more likely to get the care you need if you wait for the ambulance.
What you can do is make sure the front door is unlocked for medical workers and loosen any clothes around your neck or chest so you can breathe easily.