Recent Posts Module Excerpt Display

We are using the Recent Posts module to display the titles, excerpts & links to our latest 3 articles from our News page at the bottom of our homepage. Often our articles have headings or one liners at the beginning of them, & these are displayed in the excerpt on the homepage without any spaces or punctuation separating them. Without modifying our articles, how can we get the excerpts to display correctly? (by adding a period to lines that don't have any punctuation at the end, & a space separating the period & the next word)