If your current system is providing reliable reception as is, it's hard to suggest you change it.
Given the 2-edge path and relatively low signal levels, a high performance UHF antenna such as the DB8E, mounted outdoors, clear of obstructions is certainly not overkill. A good preamp such as the RCA TVPRAMP1R would be needed aslo.
I'd rather cable the east facing antenna system separate of the existing system. This would avoid the expense of combining filters for each channel of interest. Instead, I'd use and external tuner to terminate the second antenna system.
http://forum.tvfool.com/showthread.php?t=2882