That is very sad about her past and she is lucky to have you. All of my cats have been strays or ferals, so they are wary by nature. Having someone help you is a good idea as it is almost never a one person job to give medication to a cat who does not want to take it. Try to steel your nerves and keep in mind that you are helping her. This may not be the last time in her life that she needs medication. Some medications can be compounded into various forms, although this may not help you right now. Wedgewood Pharmacy is well known for doing this for pets.
Veterinary Pharmacy for Compounded Pet Medications
Veterinary Pharmacy for Compounded Pet Medications