For adding ‘nofollow’ attribute into anchor tag it will do a lot of changes in there because it can’t be done by using a function. But i can provide you an instruction on how to implement the changes and which file that you need to change. I hope you don’t mind because this is not our support scope but we will try to help our customer as long as we can.
About making open the link in a new window it can be done by using simple js code that I can provide for you. Can you tell me which link that you want to implement this change?