It doesn't sound like you have much of a compressor. That's your first major hurdle. Upgrade to this, as a minumum. It's all about the CFM when it comes to blasting. Once you have a compressor of this size, unless you're running a business, it's probably the last one you'll ever need!
Here's a couple of suggestions for a good blast cabinet. CL is loaded with good stuff!
Then of course there's the Barrel Blaster..................