One that comes to mind-
"T'anam 'un diabhail" is often used to express wonder
I seem to remember a poem from schooldays about somebody returning and seeing their first glimpse of Ireland
''T'anam 'un diabhail but there it is, the dawn on the hills of Ireland''

Séamus

A few more suggestions -

A Dhiabhail !

A Mhaighdean (bheannaithe) !

A Chríost !

I'm sure there are more ways too. Where is Braoin these days?

Ouh là là! ma chère Bríd - as we say in French - shocking! (I would never have dreamt that you would say that kind of thing OMD !(oh mon dieu/moun dieu!)