Help With Last Post By...

i did a search, and didnt find what i was looking for, and i think this goes in here im not sure tho. anyways.

what i want to do is pretty simple, i want to include the last post topic title on the forum index in the last post section.

Now it says
September 15th, 2002 10:11 AM
by username

I want it to say
test post
September 15th, 2002 10:11 AM
by username

do u know what i mean? test post is just the topic title of where the last post/reply was.

any help would be appreciated