It really depends on how much coding knowledge you have (or if you're
hiring someone to make necessary changes) as to how you'd want to go about things, but you have some options. One would be that you
create a child theme for ClassiPress and simply make all the aesthetic changes you wish to make so that it looks how you want it to. You can also find ready-made child themes in the
AppThemes marketplace which would change the default look of the theme (you would need to purchase one of these in addition to ClassiPress). The other would be that you use whatever theme you want on your homepage and install ClassiPress in a subdirectory, linking it from the homepage.
i.e.
yourdomain.com <== Your homepage
yourdomain.com/classifieds <== Your ClassiPress installation
Hope this information helps. Thanks.
