You can get it in the pharmacy usually. Ask the pharmacist. My local walmart usually has it, but sometimes they are out.
If you put it in the tank with your current juice, it might not get mixed very well. Maybe if you swirl it quite a bit and don't get the tank too full you might be able to mix it up well enough. Maybe in that case, just try adding a few drops at a time (swirling well after adding) and see if it progressively makes the throat hit smoother. I was sort of hesitant to recommend this, as it can be kind of involved, but you seem like you are anxious to get something you can vape.
If you put it in the tank with your current juice, it might not get mixed very well. Maybe if you swirl it quite a bit and don't get the tank too full you might be able to mix it up well enough. Maybe in that case, just try adding a few drops at a time (swirling well after adding) and see if it progressively makes the throat hit smoother. I was sort of hesitant to recommend this, as it can be kind of involved, but you seem like you are anxious to get something you can vape.