Are you working in Timeline mode? If so, all you need to do is drag to stretch the text and clip art clips so that they are as long as the background video.
DO NOT use Time Stretch on your titles or clip art! It can lead to problems. If you've already applied it, I urge you to remove it.
I am SO pleased with the help that I have received thru Adobe forums, the timelyness in the response is unbelievable. Usually if you ask a question in a forum you never get an answer or have to wait several days. Your response to adding clip art and text was dead on! It helped me immensely, little by little I am getting a handle on this program. It has not been an easy task and I have many many hours invested. Hopefully the end product will be what I am expecting. Thanks again for your time and help.
Meantime, have you checked out my free 8 part Basic Training series on Premiere Elements support site Muvipix.com?
And, if you really want to learn the program inside and out, step by step, you might want to check out my books.