Write the text file

I have a text file to read. My text file is like this:

X200876Y-140576
X220177Y-124676
X178377Y-124076
X136477Y-121376
X135377Y-110975
X135476Y-120376
X147577Y-115377
X148077Y-114076
X152476Y-114577
X165364Y-120099


I want to change it and create it in new file like this
N6 G1 Z1. F80.
G0 Z15.
N7 X220.177 Y-124.676
N6 G1 Z1. F80.
G0 Z15.
N8 X178.377 Y-124.076
N6 G1 Z1. F80.
G0 Z15.
N9 X136.477 Y-121.376
N6 G1 Z1. F80.
G0 Z15.
N10 X135.377 Y-110.975


where in new file i must add N value, G0 value which is Z15, G1 value which is Z1 value and F value whic is 80. All this values will input from text box for one time.

In X200876Y-140576 this value i must also need to do some changes i must make it like this

X200.876Y-140.576 where i need to read from backword and put the dot after the three digit.

How can i do all this.

I attach my text file here.