A quick look at your code seems to show there is basic programming problem.
If you don't have a debugger at disposal, try to execute "by hand" your code on paper (it's small so it'll be simple and fast to do.)
You'll see what your problems are.
I can see at least two. But the most obvious one is that you first increment 'TC_Alarm_Time.AlarmTime.Hours' (and wrap it around for 24 hours), but then you set it 'RTC_Time.Hours' (which I assume is the current time?), so your incremented value is just lost.
RTC_Alarm_Time.AlarmTime.Hours=RTC_Time.Hours;