Congratulations on your first power up!

You can use the market option from peakd.com if you don't want to want to wait 3 days.
I show it for Hive, but for HBD is the same... (for hive is the sell section)

First click on the down arrow and choose Market

Then you have to login in the top right corner

After that type the amount you want to exchange (Hive or HBD) in the Buy section, and press buy.

Also Good luck with growing mushrooms, I've heard it's tedious work ;)