EJO, welcome to HW. I would not be too concerned re a PSA reading that is essentially the same as the last one. There is frequently a "PSA Bounce" after brachytherapy and that is probably why your doc is not too concerned. If you get three increases in a row there may be a reoccurance of the cancer.
Re the ED, brachytherapy patients usually respond pretty well to one of the standard 3 drugs. You should be working with your urologist on the issue. Likewise with any urinary or bowel problems both your RO and urologists should be working with you re solutions. While those problems are infrequent at this point post-brachy, they do occur and should be addressed.
Good luck,
Jim