Which Version Of Windows 7 Should I Upgrade To 32 Bit Or 64 Bit

However, retailers over here no longer sell the 32Bit OEM version anymore although the 64 bit version is still easily available. I am still using a lot of applications running on 32BIT and I do not wish to buy a new computer for now. I want to extend the life of my present computer till 2020 when the Extended Support for Windows 7 is supposed to be over. Can anyone help? Many thanks.