@ Yaron10
This really isn't that unusual, the installation file is highly compressed, when unpacked it is going to be of this order.
My avast free installation/program folder is currently 408MB and this fluctuates after avast VPS updates and avast housekeeping.
The largest folder is likely to be the setup folder as that has integrity checking (copies of files, etc.) and defs sub-folder, the virus definitions one sub folder of defs containing the unpacked virus definitions database is of the order of 80MB.
As you can see these two folders take up the lions share of the 372MB you mentioned and that isn't including the other sub-folders. So I don't think that you are likely to gain much from a clean install.