In Formal letter^x, Invitations^x, Yours faithfully^x

Hello all. I am new here and I hope someone who's native in Eng. can help me. (ASAP) I need to turn this in to my boss by tomorrow. This must be a formal invitation letter. Please check my grammar and also my writing style (I know it's really bad) Thank you in advance Dear Sir or Madam, ...

OK, darlin’ I’ll get the ball rolling for you. I’ve never had to do it myself but here goes. (Keep askin’ if this isn’t any good for you – smile) Dear Sir (Sir is back in fashion) I am writing to acknowledge receipt of your invitation to the ‘Totally Marvellous Hot Air Balloon Expo in...