The strainer is made of brass screen (like window screen if you are old enough ;)).

As to parts, I would suggest whomever sold you the rebuilding kit would be your first call.

There are also other places that offer carburetor parts.

Jon.

Good carburetion is fuelish hot air
The most expensive carburetor is the wrong one you attempt to modify.
If you truly believe "one size fits all," try walking a mile in your spouse's shoes!
The Carburetor Shop