LG V VX-9800

i've been using the imtoo program to convert all my movies to .3gp format.. the quality is great and all, but the problem is.... when i maximize the screen size while watching the movie it gets fuzzy, but its fine when i don't maximize it.... is there a way to make the video size bigger when i use the imtoo program to convert my movie files??? i can only make the video size 176x144. if i try to change the size i get a fail message and cannot convert the movie file... am i don't something wrong??? or did i just get a bad imtoo conversion program??/ any help will be appreciated. thanks.