How can i write to text file and then to add/append new text ?

This is the code. First if the count is 85 im writing some text to a new text file.

Then in the else i want to add the new text to the existing file and not ot create a new one.

Also the format of the text file should be like this:

extendedPoints count = 85 , clouds count = 29 | extendedPoints count = 88 , clouds count = 30

1. {X=181.8569, Y=172.4}
2. {X=180.7902, Y=171.8667}
3. {X=181.3235, Y=172.1333}
4. {X=180.2569, Y=171.6}
5. {X=179.1902, Y=171.0667}
6. {X=179.7235, Y=171.3333}
7. {X=178.6569, Y=170.8}
8. {X=177.3235, Y=170.8}
9. {X=177.9902, Y=170.8}
10. {X=176.6569, Y=170.8}
11. {X=176.7902, Y=171.4667}
12. {X=176.9235, Y=172.1333}
13. {X=177.0569, Y=172.8}

The left side is when count is 85. The right side should be the ELSE part and there should be also a list of coordinates from 1 to...

In the end the text file for example should look like this:

extendedPoints count = 85 , clouds count = 29 | extendedPoints count = 88 , clouds count = 30

1. {X=181.8569, Y=172.4}                        1. {X=181.8569, Y=172.4}
2. {X=180.7902, Y=171.8667}                     2. {X=180.7902, Y=171.8667}
3. {X=181.3235, Y=172.1333}
4. {X=180.2569, Y=171.6}
5. {X=179.1902, Y=171.0667}
6. {X=179.7235, Y=171.3333}
7. {X=178.6569, Y=170.8}
8. {X=177.3235, Y=170.8}
9. {X=177.9902, Y=170.8}
10. {X=176.6569, Y=170.8}
11. {X=176.7902, Y=171.4667}
12. {X=176.9235, Y=172.1333}
13. {X=177.0569, Y=172.8}

The left side is when count is 85 and the right side when its getting to the ELSE part in the FOR loop.