How do you say Granduncle in Mandarin?

[Angeline]

I am looking a for a website that tells us how to address all our relatives in Mandarin. I have trouble with some of the more remote relations. E.g. how would you address the husband of your grandaunt (姨婆yi2 po2 and gu1 姑婆po2)? What about your mother's cousins - any difference if they are from your mother's maternal or paternal side?