Okay.. I checked the version of the Tamron I have, and it's the 572DE which has 1:2 ability. The older versions (which I believe this to be) won't come near this. As far as macro ability, all you can do is get as close as possible with it in foucs. That's as large as it gets, sorry. No switch, not much macro ability on the Tamron 70-300. You can check the version I have, and the lesser one here:
http://www.bhphotovideo.com/bnh/control ... Submit.y=8
There's very little price difference, but the maco ability is only a 1:3.8 on the older version. Some even older lenses wouldn't be as good as either of these. So it's very important to know what you're buying before you purchase.