http://www.tf2outpost.com/trade/4522868- Highest offer on outpost by a longshot. It's 20 keys, very recent (I think the 45 key offer can be safely discounted as a troll given the 24 key buyout). I'm still inclined to agree, it's within your range and I don't see anyone offering higher than that, or even anyone else offering similarily any time soon.

http://www.tf2pricecheck.net/Thread-PC-Orbiting-Fire-Copper-s-Hard-Top- Put at 1 bud tops, most agree that 20 keys is a good pricecheck on it