-Beginner a77 - and suggestions about tamron PS 70-300 USD Di

I personally enjoy taking photos (about 60 % nature and animals, the rest is for close up and portraits, -rarely macro). Making video is also of the part. I had never own a camera until I recently  bought a77 body.
My first and only lens is a Tamron  PS 70-300mm USD Di. I bought it after  investigating  and reading its reviews. At that time, Sony SAL18250 held my interest too.

I find the tammy 70-300 lens good, nice bokeh, the autofocus noise/speed is acceptable...

But, its minimum focus distance (obviously) and the fact I couldn't shot a (big) subject in its entirety in some situations disappointed me a little bit. Its like I have anticipated the need to take pictures of distant subjects and get close to them (from a 'long' distance...)
So,
    - should I return back the tamy 70-300 and replace it : in this case do you suggest me to buy the SAL18250, or another lens?
    - should I keep my current lens and  buy another one to cover the range < 70 mm ?
    - any other advices ?
In all cases my budget is limited...
Thank you for reading, your suggestions are very welcome.