With a bit of work you can publish data out of Aggregate and send it elsewhere for consumption, including pushing it into a Postgresql database. Most of the effort is in setting up an endpoint to receive the data and process it accordingly (ie getting it outa Aggregate aint that hard). Please take a look at the above link for more info on exporting data from Aggregate.
You might also want to look at this recent thread, there may be something in there of use.