I am not familiar with the speakers you have, but for a 7.1 setup, with floor standing speakers, i would be looking into an amp as well. even if it's something used and cheap, it'll feed the speakers closer to what they need then the receiver can.
also, you say you want floorspeakers because you want more base. Again, without the right amount of power, they will not give you the clean sounds and base you want. Also, I found out that there;s simply no replacement for a sub. i bought my floor speakers thinking I would not need a sub... I was wrong... the sub made a big difference in the overall sound of the system.
I'm still new to this, so take my comments for what it;s worth to you, it's just what I have experienced thus far.