You are almost there, just a few notes:
1. Time is in seconds, so to add 1 hour to a time, you must add 3600;
2. In conditional formatting, the LAST condition to evaluate true takes over, so your conditions need to be in the opposite order;
3. I believe that:
Get(CurrentTime) ≥ Self - 2*3600
is a bit more intuitive than:
Self < Get(CurrentTime) + 2*3600
Thanks so much! That worked. I didn't know about the time being in seconds or about the order of the conditions. And your revised formula worked perfectly. Much appreciated!