Getting fit! Advice

So I'm on my way to get a gym membership. My son is 9 months old and I've made excuses long enough. I'm eating better now than I ever had but I really need to be more active. Now I know that I need to do cardio. But one thing I really love to do in the gym is lift weights. So my goal is to work out 4 days a week and I want to start lifting heavy! I loved my body the most when I played volleyball and was in weightlifting. I've got 80 lbs to lose! With eating healthy I've already lost 10. Any advice is appreciated!