Since you've admitted that you're not a handy person, have you considered the cost of having your modification repaired?

An easier solution would be to run the wires through a window.

Get a length of thick (at least 5x the diameter of your thickest cable) closed cell foam (a pool noodle could even work) and cut it to length to fit in the windowsill. Cut a 3-5 inch slit through the center of the foam, enough for you to push the connectors on the wires through. Place the foam in the windowsill, and close the window as tightly as possible. Cut a dowel or broom handle to length such that when wedged in the window frame, it compresses the window into the foam. Use "no residue tape" to seal up all edges of the window and foam for weatherproofing, both inside and outside.