You can't properly do the job w/o being access to an AC machine which first recovers the old freon and weighs it (thus tells the tech the exact weight, charge of freon that was in the system), then evacuates the system which removes all moisture, then adds the correct charge by weight.
If you're planning to use one of those kits from a parts store with the 1 lb cans, all you can do by yourself is add freon and you'll be guessing when you think there's enough freon added. With a 1.65lb total system charge, it'll be easy to overfill the system and too much freon is just as bad, if not worse than not enough. If there's too much, the compressors blow off valve will blow out freon when the pressure exceeds the limit and it'll then be low again, back to square 1.

It's best to have it done by a shop where they have the proper AC machine. Do have AC dye added too if it's not already been done so that if it slowly leaks out again, they'll be able to see the dye.