Easiest way to do it would be to cheat, and separate the lower text.
<p><img class="left" src="" alt="" /> INSERT TEXT HERE</p>
<p>This way you will at least get a guarenteed gap into the next bit of content</p>
Its hard to really give advice on it though, without seeing what you are trying to achieve. I'm pretty new, but will try to help as I can.
Mouse
EDIT - Added my CSS babble for left floated images - Might be handy to pull apart and bugger around with.
p img.left {
float: left;
margin: 0 9px 0 0;
border: 1px solid
}
p img.right {
float: right;
margin: 0 0 0 9px;
border: 1px solid
Margins are so Text doesn't hug the picture