We actually can do a point release Python upgrade for you :-)
The versions of Python that you have installed depends on the system image associated with your account; you're on our older "classic" system image, and the new "earlgrey" image has Python 2.7.12. We can easily switch your account over to "earlgrey" -- it's just a simple database change on our side.
But there is one catch; the versions of many other things will be upgraded at the same time. Many of the pre-installed Python modules will be upgraded, which means that any code you have that depends on the older versions of the pre-installed modules may break if it's not compatible with any API changes.
There's also a slightly more subtle issue if you're using virtualenvs -- virtualenvs can have issues with point release upgrades, so ones that were built for (eg) Python 2.7.6 are not always compatible with 2.7.12 -- so you might need to re-create any virtualenvs.
Anyway, we can certainly switch you over to the "earlgrey" image if you like -- just let us know.