as Roy0110 says, if you can cable you should, otherwise you could try some homeplugs with wifi extenders in them assuming you need wifi in those areas.. if they're fixed equipment, you could just do homeplug to homeplug.

for an example of homeplugs with wifi...
Code:
http://www.netgear.co.uk/home/products/networking/powerline/XWNB5201.aspx