Hezz

You need to buy a pair of cycling shoes 2 sizes large so you can wear two pair of thicker wool socks and the shoes still be a bit loose fitting. Try some toe covers instead of the shoe covers if it is dry as this allows your foot to breath which will keep them warmer. If it is wet substitute a neoprene sock next to your skin and a thick wool sock over that then the shoes and the full shoe covers. You need the neoprene sock as a vapor barrier since most of the shoe covers are not breathable and are designed to be mostly water proof or water resistant. This also means that it wont let your foot breath either and so you need to trap moisture from your foot next to the skin to keep the wool sock dry.

This works pretty good. IF this doesn't work for you down to 30F or lower then you may need to use a winter cycling shoe two sizes bigger with the shoe covers over them. Or a winter lightweight hiking boot with some platform type pedals.

ALso, the Goretex shoe covers don't add any insulation so they are probably not warm enough for conditions below 45 degrees.