Trying to understand nature of hacking

It looks like your server is using Apache’s Combined Log Format. So here’s what’s actually in your logfile lines: {Remote client's IP address}
- {Remote user ID, generally unused}
- {Authenticated user ID, unused in most cases}
[23/Apr/2013:17:41:19 +0530] {Date}
"GET / HTTP/1.1" {Request - here they asked for your site's home page, essentially}
200 {Status code -- 200 = Success}
19928 {Transferred data -- your homepage is 19928 bytes}
"" {Referer}
"Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; ru) Opera 8.01" {User-agent / browser}

It appears that someone (or some ‘bot, or other software) at IP clicked on a link to http://[your site]/ on the site at

These two entries look pretty innocent to my eyes — though I will admit I’m not an expert. Is there anything around the same time in your access or error logs?