My first thought is the styrofoam heart that you buy at your local craft store and either painting it or covering it with red material (Because it does chip off)
The bell you can also get at your local craft store, you can paint it or keep it the original color. Use a string to attach it, a fairly heavy duty one depending on how much your bell weighs. Attach it too the heart not the ribbon.
Get a ribbon (for the ribbon like thing right above the bell) or if you're creative get some material and make a pattern that looks like the riboon and recreate it. Get heart shaped felt or foam and glue it over the ribbon. (Draw the design on it) Do the same for the green thing and glue it all to the heart. This seems a little complicated but if all else fails, I can try it myself and make a tutorial.