Hi Aggreen,
On the Repeating Table Properties - Rules button - No condition - Set
my:<field1name> = ../my:<repeatingTablename>[1]/my:<field1name>
my:<field2name> = ../my:<repeatingTablename>[1]/my:<field2name>
The above commands tell the repeating table that each time a row is added, retrieve the value of the first row ([1] part), field and assign it to the new row field.
Hope this helps/works.