How can I improve my EC?!

<p>I immigrated to United States very late (at the end of my freshman year) from China. Therefore, I struggled with my English for one year. Now I have been a junior; however, my EC is very week. </p>

<p>Here are my ECs:</p>

<p>Presidents of two clubs
220 hours volunteer in a hospital
Swimming Team of a pool (I swim slowly because I have stopped swimming for almost two years)
Members of several clubs
School Science Olympiad</p>

<p>I don't have the ability to win regional science award even though I am interesting in science. </p>

<p>How can I improve my extracurricular activities? My dream is to get into top ten universities in American, but now for my EC, it is only a dream! Help!</p>