Hi Rubeaz
The Irish records can be difficult enough as it is, but the earlier you go back in time the more difficult it becomes. You would really need to know which church they attended, and then hope that some records exist for that church. There is no central point where you can search online for this. We have some links here which may be of use:
http://talkingscot.com/forum/viewtopic.php?t=9820
and also try the IGI just incase!
You could have a look at the Grifiths Valuation and get a picture of where the those with surname Campbell were at that time, but with your family in Scotland by then, it may not be a great help.
Many of us are "stuck" much later than that in Ireland, the 1830s in my case, with very little hope of being able to move back in time just due to the records not exisiting.
Also see my previous reply regarding your Campbells
http://talkingscot.com/forum/viewtopic. ... highlight=
Best wishes
Lesley
My gg grandfather Neil Campbell born to parents Neil Campbell and Catherine Whitelaw.