Awwwwwww *hugs*
Yes, it's not a problem that the petitioner is sending it. Just adjust some of the wording on the sample cover letter and you're good to go!
Updated!
Added!
1. As I mention in the wiki (have you read that yet?), if you give over both email addresses, then the DS-261 becomes a moot form as all correspondence from NVC is sent by email, so it doesn't matter who you choose as agent, even if that person is abroad.
2. Yes, it's the same thing as what they mail you.
