I've been looking for these exact same metrics for some time now. It doesn't seem like the Analytics API currently supports querying for those specific metrics. I genuinely hope I'm wrong, but neither the
Data Query Explorer tool or the
Analytics Dimensions and Metrics Reference Guide shows how to query for this data.
I hope that I'm wrong on this second point too, but I assume that these metrics aren't available through the API on purpose. It seems that Google only wants Analytics Premium subscribers to be able to manipulate their sales attribution data, per
http://www.google.com/analytics/features/attribution.html.
If someone should have an update or a confirmed answer, I'd love to hear it too though. This is data I'd really like to get my hands on through the API.