software or hardware???

["Jenny Daskalaki" <jendask@gmail.com>]

Hi everybody
I am new to this forum...
I need to know your opinions on this issue:
We are a two (or sometimes three) man band playing many different
instruments (drums, guitar, bass, flute , vocals, moog, percussion
etc.).
We like jamming so ideas come up during improvisation. We have a PC
recording interface (Firepod) and a mixing desk. We need to be able to
make loops while jamming without interrupting the performance.
Recently we bought Boss rc 20 xl but it looks pooer to our expectations 
because:

1) Quantize affects ONLY the end of the loop phrase but the rest of it
,so you have to play it absolutely right!!
2) During overdubbing you only can delete your last phrase but you
always listen to the previous on the stack.
What I mean exactly: Let's say while you are jamming you start playing
over an already recorded phrase. You come up with another phrase OK
you overdub it, now you have two phrases (in the same phrase track),
then you come up with a third one but gradually you want for example,
to listen only to the first one and third one . Well you really can't
do that. You can only delete the last phrase on the stack. And you
will always be listening to the first one unless you completely change
program!
3)Also, the most important is that when I try to change the tempo the
sound becomes terribly damaged! (although there is no change of pitch)

Is there a hardware setup that could achieve these or should we use
software like Live Ableton in combination with midi foot controllers?