Sadly you can't. The model Adobe has set up is that you need to send the file to Illustrator, and can only send to Illustrator CC - not even CS6. Even though I have CC and can use the feature, it is really annoying that it can only spit out low quality pngs as sometimes I want to just knock up something quickly on my iPad, export it and mail it on. The only real option is to stick to using Ideas.
Updated: It looks like they may have lifted the restriction on you having to have a Creative Cloud account as of the last release, so maybe you can now export to CS6