The first image is what I call 'over-scanned' and will not be workable. You're actually seeing the pixelation from the magazine's printer. I think most magazines are printed at under 150dpi, so if you scan it any higher than that those will be your results.
You'd actually get a better source scanning it at a lower resolution, and then trying to blow it up and do some sharpening of that image if you want a larger size.
Another thing I've done with decent results in the past is photograph the image on the page with a digital camera in macro mode. Depending on the resolution your camera shoots at, you can still end up getting the printer pixelation as a result though.
>8^)
ER