There are no churches on the Har Habyis only 2 Mosques (Al Aqsa and Dome of the Rock)
The Church of the Holy Seplucre is about halfway between the Jaffa gate and the Kotel Plaza along the Arab Bazzar street (Or whatever you call that Arab Bazzar from the Jaffa Gate to the Kotel).
The supposed place of where a cross was carried the Via Delorossa most go on after leaving the Tunnel Tours of the Kotel, the other side is the Via Delorossa , It is not on the Har Habayis