Dear Donation Committee,
I am a member of the (name) organization. I have taken on the roll of sponsor representative. (name) is a non-profit group of parents who are offereing communication, leadership and encouragement to our cheer team. This parnets group has just recently beeen formed but has already made a significant impact on the State level. The cheer team does several things during the year to support our community. Druing the community days last year the girls all helped out at the local blood drive, they did face painting for chilren and they have done daycare services for several of the business meetings in town. At their state competition last year the squad place third in the spring and the fall. As a parents group we are fundraising to purchase them Cheer Mats to keep them safe and to host the State Cheer Competition. When we aren enough money to purchase the Mats we will be the second school in the state of North Dakota to own them.
I was wondering if your company would be interested in financially helping our (name) cheer team with these importand projects. I hope that you will gladly  accept to sponsor us in the state cheer meet and with the purchase of our mats.
Enclosed is a pledge card with a return addressed envelope for your covenience, please make checks payable to (name) if you have any question please feel free to call me at (phone number). I look forward to hearing that you will help us out in this worthwhile projects.

PS: As you can probably tell, I didn't modify much  to  your letter. There were some spelling mistakes which I try to change, apart from  that  the general idea is appealing. Meanwhile I think that your conclusion should be changed for example you could tell why you have come to them not someone else, and maybe mention their benefit from doing so. Would you personnaly sponsor anyone who comes to you and asks for help? I honestly doubt, thus at least you should tell them why you have chosen them and... Well it's what I think so you also discuss with some member of your organisation and see what they would have to say.

Hope it helps

All the best