[squid-users] memory hit ratio

Could someone please give me an idea of what am I doing wrong on the
squid.conf ?, I can't get more percentage on "Request Memory Hit Ratios":

Average HTTP requests per minute since start: 1470.9
Average ICP messages per minute since start: 0.0
Select loop called: 68814496 times, 7.975 ms avg
Cache information for squid:
Request Hit Ratios: 5min: 53.2%, 60min: 52.4%
Byte Hit Ratios: 5min: 28.1%, 60min: 27.5%
Request Memory Hit Ratios: 5min: 9.3%, 60min: 9.0%
Request Disk Hit Ratios: 5min: 34.7%, 60min: 30.2%
Storage Swap size: 19382004 KB
Storage Mem size: 131096 KB
Mean Object Size: 12.11 KB

The pc is a Pentium IV 2.0 gb and 512k ram, RedHat v9.0

Also, I am getting a lot of this:

Cache Clients:
Address: 68.73.68.230
Name: 68.73.68.230
Currently established connections: 0
ICP Requests 0
HTTP Requests 1
TCP_DENIED 1 100%

This ip does not belong to our network and is not on our Squid ACL, does this
mean that they are trying to use our Squid ?, almost the 25% of the Cache
Client List reported by the cachemgr are ip's from outside our network.

Thanks in advance,

Rolando