You are out of luck.
AE needs lots of RAM to work. 32-bit operating systems can't access more than 4 GB of total system memory. That means that, if you have a tiny GPU that only has 512 MB of video memory on it and your computer has 4 GB of RAM installed, your system will only see approximately 3.5 GB of RAM.
AE needs 4 GB of RAM minimum to run (in my opinion 8 GB is the minimum to actually use it reasonably).
Making a 32-bit version is impossible unless they created an entirely new piece of software that could get by on less than 4 GB of RAM. And it would run really slowly and nobody would like it. So, as Rick says, you're flat out of luck unless you upgrade. It's fairly cheap (or free) to bump up to a 64-bit operating system, so, you know, you could do that.