[Dave Canon]

Given that you have taken a lot of shots in very similar lighting conditions the you should be able to apply settings to a batch of files in Rawshooter. I only have the free version of Rawshooter but there is a buttom towards the top right which allows you to save the setings applied to the current picture. You can then select any or all of the other pictures in the folder and paste those settings. This is better than an auto-levels as you can make a simple or a complex set of corrections to a single picture and then apply to hundreds of others in seconds. What is vey useful is that you do not have to paste all of the settings but can just select some of them (e.g. tonal corrections). I am sure that this feature will be in Rawshooter Premium, if it available in the free version.

Also, even if you cannot run Lightroom now, I would get your free copy in case the offer is time limited. You may wish to benefit from it in the future.