Hi Yamila,
I won't be able to be much help to you but I'll try. Write to me at
nheydt@monmouth.com "UGALDE [comes] From ughel - dyr: high land, upland. Found only in Liskeard area."
This is from "A Handbook of Cornish Surnames" by G. Pawley White. It means that Ugalde is from the Cornish language.
Were your Ugalde ancestors miners? That's what the Cornish are most famous for and the reason they migrated to places all over the world.
One of your best bets is to look on the Internet at the Cornwall Family History society site. They have over 5,000 active members and probably several are searching for Ugalde. Write to me directly and I'll suggest whatever else I can.
Nancy