You can still join the Adobe Photoshop Photography Program that gets you Photoshop CC
and LR 5 for $9.99 a month - as long as you sign up before December 31, 2013.
https://creative.adobe.com/plans/offer/photoshop+lightroom
Lightroom and Aperture are both PIEware - image database managers that have a parametric Raw conversion/editing function. (PIE = parametric image editor).
So if Aperture didn't have the kind of editing capabilities you needed, Lightroom likely won't have them either.
It is worth noting though that Lightroom's Raw conversion/editing module - the Develop module - and Photoshop CS 6/CC Camera Raw both use the same software - Adobe Camera Raw (ACR).
Photoshop Elements has about 1/2 of ACR's tools and functions.
That leave Photoshop Elements (consumer grade) , Photoshop CS 6 (pro grade), or the monthly pro grade subscription service Photoshop CC (Creative Cloud)- if you want Adobe software.
There will be no CS 7.
Adobe's most up to date professional grade software - the Creative Cloud is now only available by subscription.
Photoshop CC includes 3-D and video editing functions CS 6 does not have, and CS 6 will not receive any of the updates CC gets.
Both Photoshop Elements and GIMP are limited by only being able to do 8-bit depth edits.
Bit depth is an important aspect of image editing. You can learn more about bit depth here -
Photo Editing Tutorials
I've been using Photoshop almost daily for well over 10 years and I still learn more ways to use it more effectively, either by trial and error, an epiphany, or learning a new way to do something from a Photoshop expert.