if you could post a pic or two of the bow, others may have interesting ways of adding weight. I have several, but only having dealt with self bows. Perhaps if you can recurve the bow, you can will get more draw weight. Or tie on siyahs, or just build up the tips of the bow a bit on the back. The result of all thee is the draw length stays the same, but forces the wood to bend further, storing more energy. You could cable back it with string bridges, pike an inch off each limb, and re carve your nocks. But again, pics would help. How much weight are you trying to go for, and where are you at?