From what I see, RDP on port 3389 is being used only within your home LAN. If "every man and his dog" has access through your router to your private LAN, you've got bigger problems than securing port 3389!
fyi, this business of changing a protocol to use another port falls in the "security by obsfucation" category, i.e., it's not very effective. Although RDP is subject to man-in-the-middle attacks, it seems to be pretty secure otherwise. Better to worry about password complexity.