Marty,
You've still got about a month of forage time left, depending on where you live. It's not necessarily the most productive time but it works. Additionally, you could "extract" your flow hive, then put the second hive body on top of the first one. If the second hive body has drawn comb, then add the wet extracted flow hive on top, if not give them a week to draw some comb in the second hive body before putting the wet extracted flow hive on top. The goal is to have them clean out the flow hive and put the remainder it in the middle box. After it's been cleaned out, I'd remove it until next year so the Freds concentrate on filling the second hive body and don't get distracted by the empty Flow Hive, and they don't need to air condition the extra large brood volume. I'd then feed them if they'll take the syrup.
With respect to buying honey frames, Be careful from whom you purchase. I have nothing against anyone specifically, however you're introducing "unknown" equipment into your hive and don't know what diseases/poisons might be present. If you want, though, you might post a request on the garage sale forum.
