There are three simple ways to increase your trigger pull. The simplest is to tweak the sear leaf of the sear spring forward a bit. Your sear spring has three leaves; left to right, they are the sear leaf, the disconnector leaf and the grip safety leaf. If you take out the spring and bend the sear leaf forward a little, it will increase the trigger pull. I'd do this before even considering any other action. One can often make a difference of one to one-and-one half pounds just with adjustment of the sear leaf.

The second simple way is to install a heavier mainspring. I don't know what weight mainspring DW puts in at the factory, but hardly anyone still installs a full-weight 23 lb. mainspring anymore, except Colt (on some models) and Springfield (some models), based on what I've witnessed over the past few years. Most seem to be in the 19 pound range, which is what I usually install when doing a competition trigger job on a 5" .45, or I sometimes go all the way down to a 17.

Third, one can alter the angle of the hammer hooks, but that is a job for someone with some experience. There would be no need to replace the hammer or sear unless one or both were defective or had been screwed up by someone.