No you can't export, I believe Marketo is working on it.
Looks like it will have to be screenshots for now until the feature is released.
What kind of report are you looking to create? Are you talking on the salesforce.com side or in Marketo? There are a number of email reports but more information would be better so that we can help.
I'm talking about Marketo email insights.
Just want to export results of analytics/sends.
Looks like this function has not yet released.. thanks anyway