can you add extra glass panels to a upvc door?

we have a upvc front door with 2 very small glass squares at the top which does not let in enough light, is it possible to add extra glass to the door ?there are two fake panels with beading under the 2 small windows could the door be cut and glass added and then put new beading in to hold them in? if so can it be cut with a jigsaw,it is too expensive to buy a new door so we were looking for a cheaper alternative.