Unfortunately, there isn't if you want to keep that 4th stick.
When you add another stick to any particular channel, the interleaving reduces the speed (the has to switch between sticks, and the slowest channel dictates the speed of all other memory channels).
Hence all sticks run at 1066.
Now keep in mind, it's far more likely that you'd benefit from the increased capacity rather than the increased memory speed (this is useful for say a cluster). The reason for this tends to be storage, as it's drastically slower than memory (even if the application is completely stored in memory, it still has to wait for data to be written to the disk as well as user input).
So unless you're trying to solve the fundamental equation of the universe type of usage, you'd almost certainly be better off keeping that additional stick installed (ability to retain more information in memory reduces the need for page outs).