How do I reinstall an older version of Aperture from the App Store?

Question

Hello,
I have an older Macbook - 13 inch early 2008. It is still running fine on 10.7.5 Lion, but can't update to a later version of OS X, as it is not compatible. I have Aperture 3.4.5, which I purchased from the App Store.
Following a hard disk problem, I've reinstalled the laptop, used software update to get all the latest patches, and have recovered my files and applications from my Time Machine Backup. Unfortunately, Aperture is no longer able to open files from my Sony Nex camera ("Unsupported Image Format" message") even though it worked before I rebuilt my Mac, and is listed as supported under Aperture 3.4.5. I've done all of the "Repair permissions", "repair database" and "Rebuild Database" things, but it hasn't helped.
I've tried to fix this by removing Aperture (in case my Time Machine backup version is in some way corrupted) and reinstalled from the App Store, but the App Store won't let me have Aperture anymore, even though I've paid for it, because my system is no longer compatible with the current version, 3.5. I can't see a way of downloading a full copy of the older version compatible with my system. I can see updates for Aperture listed at http://support.apple.com/downloads/#aperture, including Aperture 3.4.5, but these require a copy of Aperture 3.0 or later already installed to update, and even if I run the 3.4.5 update, it tells me it won't work because my copy of Aperture is from the App store.
Can anyone help me find a way of navigating the App Store or Apple web site to get the copy of Aperture 3.4.5 I have licensed from Apple?
Many thanks.

Answer 1

@léonie
Thanks for your help with this. I've downloaded the latest RAW support updates supported on my machine - V4.09 that seems to contain all of the RAW formats for previous updated including V4.06, which includes the NEX 3N, my camera. After a short while (there seemed to be some sort of background processing ging on in Aperture) it started to allow my NEX 3N photos to be viewed. Some of the thumbnails were corrupted, but if I made a slight edit in each of these files, the thumbnails updated and all was well.
Prior to this, I raised a call with Apple, because the inability to reinstall software from the App Store that I've purchased from in App Store to a machine that supports OSX 10.7.5 and no later strikes me as a problem. I need to know that if my Time Machine backup fails and I need to reinstall, I've got somewhere I can go.
The support people at Apple were very helpful, and it feels like they recognise this as a problem, and are working to resolve it behind the scenes. The App Store will not allow me to download the last version that works on my machine at the moment, but it sounds like Apple is thinking about how to do this. In the meantime, they are shipping me a copy of Aperture 3.0 on CD, and sending me a registration code. This will solve my immediate problem.
This does make me wary about using the App Store for purchases in the future. I don't upgrade my hardware that frequently - I have no real need to as it just keeps working - and so not having physical copies of installation media for when the applications stop supporting my OS is a worry. On the face of it, maintaining prior versions of the software for older machines to download from the App Store seems like a reasonable solution, but they are not there yet, and there is no real commitment for them to do this. Anyone who doesn't back up their Apps in Time Machine (probably the majority of users) could loose them altogether when Apple moves on, and cuts app support for older OS versions.
Thanks to @léonie and @Frank Cagianno for your help.
Andy