I'm 29 weeks and I've gained about 35 pounds. I was at an average weight for my height so I think I'm gaining an appropriate amount of weight. If you were heavey before pregnancy you may not need to gain the full weight that Dr. Luke recommends, likewise if you were underweight before pregnancy, you may need to put on more weight than Dr. Luke's guidelines.
It sounds like the other ladies here have given some good suggestions for packing on the LBs. Good luck.