I am a little confused about your question, but:
I found the only way to do something like this is to go to find each - or space (which Google Docs will find) and insert a "dummy" character.
Then do a search and replace with ,
Then copy all, delete all, go to the html mode and paste it.
Go back to normal view and you should have an extra space after each.
If you are trying to do this:
(I.e. the equivalent of searching for "^p-" and replacing it with "^p^p-" in Microsoft Word)
Go to html mode, and find out which tag is causing the line break, (could be div tag or a br tag (I can't get the tag characters <> to show), copy it, go back to normal mode, paste all,use copy and replace on whatever it was (br, or div) with two of them, copy, delete, paste back in html, and you should have the extra line break. Hope that helps.