What do you mean by "proper weightlifting"? I consider heavy lifting doing exercises like deadlifts or power cleans, which can be really dangerous if you don't know how to do them properly. I would suggest getting a trainer if you wanted to try these, since you'll be lifting a LOT of weight and can easily hurt yourself.
Some days I'll just find heavy things in my yard and lift them (controlled and with a straight back!), lug them, or run with them over my shoulders until my arms give out. I never did much "heavy lifting" in the past (I've been weight lifting for about 3 years?) and got pretty strong with dumbbells (just keep increasing the weight), bodyweight exercises (especially during a HIIT workout,) and PULL-UPS!
Oh, and online videos are REALLY helpful. Watch them, take notes. Crossfit.com has a section full of instructional videos. But I'm still warning you...Be careful and take things SLOW! You don't want to throw your back out!