Strong box is good, but Proxy Pass is by far the best. You can set it to block passes coming from as low as 3 different locations. Its fast also... You will not be waiting 10 minutes while they suck your BW.
We have 8 solo sites and I know what you mean. Proxypass is the best on the market. We had Pennywise and it sucked ass.
And yes, if you have enough content 24.95 or 29.95 is not to much for a single girl site. If fact... we found they convert much better at the higher monthly rate.
http://www.proxypass.com/
They are awesome.. they install it for you... 24/7 support that really works. I think its 50.00 a month that we are paying, but way worth it.
Not a better program out there... and trust me.. we have tried them all.