Let's start from the fact that your prescription is just plain wrong!
If you are myoptic, then ...
Reading, Using a PC, and Distance, all need different prescriptions.
You should seek out a good optometrist and get a proper test. However ...
My suggestion would be to go into a supermarket (think Walmart size, or Tesco) and check out their reading glasses.
You can find what strength works for you at reading distance, and at the distance that works for a monitor.
This will almost certainly mean two pairs - but since each one only costs peanuts, this is a good way to start.
The optometrist will sort you out for distancce vision.
What you don't want yet is varifocal lenses - they take a lot of getting used to (but you may eventually need some).
I get by with bifocals, but I have a large monitor set at 1024 x 768 rather than a really hi-res setting. This means that text on the screen is just that little bit larger. Then you can adjust brightness and contrast so that you can work at a comfortable distance.