The website you're referring to is Krista Dixon, right? If so, it's a good one, I agree.

Rather than a bar, I would get another set of heavier weights. A bar makes your arms & shoulders move in one plane. Not good. With regular weights, you can slightly adjust the plane of movement to accomodate any shoulder, elbow, etc. issues you might have.

Let's take shoulder work, for example. Free weights also allow you to adjust your hand position. For example, an overhead shoulder press can be done only one way with a bar. With weights, you can push overhead with your hands facing each other, push one at a time or angle them out slightly. Also, you can do side lateral raises with weights (to hit the medial head of the deltoid).

Don't forget the good old standbys like push ups. Those work your core as well as your chest, triceps and anterior deltoid. Varying your hand position lets you hit different areas.