JH,
Not a bad start, but if I may, I'd like to recommend a few things as I've just gone through this process with many author friends of mine... Here goes...
I would recommend that you break this down into a 5 paragraphs: 1,2,and 3 will tell the story. You want this to read much like the backcover would. Paragraph 4 needs to include word count, title, the fact that you have it available for submission, your target audience. This is also a great paragraph to insert any similarities to the "house" you're submittting to. Paragraph 5 will include all your credentials: writers groups, any kind of anything that you've published. Have you ever been a regular contributor to anything? That gives you credibility as well... And of course, your
Thank you for taking the time. I look forward to hearing back from you. (shows them you are waiting and anxious)

Good luck, this isn't an easy task. I should know, it took me weeks to perfect it. But remember, you could perfect forever, so when you get it in format, it sounds fabulous... send it off!!!!