Android App Help (simple update)

Hello, I had an Android app created for me a little while ago. I would now like to submit it to the Android market place but there is a problem with the certificate. I'm getting the following error when uploading the APK file: "Market does not accept apks signed with the debug certificate. Create a new certificate that is valid for at least 50 years. Market requires that the certificate used to sign the apk be valid until at least October 22, 2033. Create a new certificate." I have all the code and really just need a new certificate so I can upload the app. I can provide a great rating. Thanks