How to find a public cache_peer parent or connecting to Internet without parent

Dear all,

I need help in the following problem
Until yesterday we forworded our reqeuest from our proxy to the ISP
(UUNet) proxy by using:
cache_peer 192.76.144.xxx parent 3128 3130 no-query default

Since yesterday there is a problem
"
The following error was encountered:

Unable to forward this request at this time.
This request could not be forwarded to the origin server or to any
parent caches. The most likely cause for this error is that:

The cache administrator does not allow this cache to make direct
connections to origin servers, and
All configured parent caches are currently unreachable.
"
UUNet told us there is a problem with there squid and they don't won't
to support forwarding any more.

Now the questions:
- Can we use public "cache_peer parents" ? Where can I find that IPs ?
- What do we have to configure, when will try to use the internet
without a "cache_peer parent" (squid is behind a checkpoint Firewall)


Any help is greatly appriciated - we have a real problem now !!

Thanks

Juergen