First and foremost ... ensure that the bicycle is set up to fit your properly. When your bicycle fits you properly your choice of comfortable handlebars and seats increases.
Secondly, after you have ensured that the bicycle is set up properly, talk to your LBS (or other LBSs in the area) about trying saddles. A good shop will let you try saddles for a week, a better shop will let you try saddles for a month, a great shop will let you try saddles for 6 months.
You might talk to them about trying handlebars too. Good LBSs will let you try handlebars.
And finally ... start working on your core. When you have a strong core you can sit on a bicycle with good posture and be comfortable for longer, and again, you increase your chances of finding a comfortable saddle and handlebars.