I think your comic looks pretty good in that resolution.
As for my comic, I use MS Paint and Paint.net. MS Paint to plan, rough, outline, ink, and color. Paint.net is to add everything together (the frame, the speech bubbles, etc.)
The resolution is huge: The last comic was 4000x6000 and that was for a 3 panel strip. The height gets bigger the more panels there are. I think it looks nice and sharp, even when shrinking it to fit Tapas.
EDIT:
...and this topic is one year old and you're probably gone! Agh! This is one of the problems I have with these old post being resurrected.