I just looked up the spec sheet on the line you specified (http://www.hikvision.com/en/epro2.asp?id=83&classid=127&bgclassid=104&act=&classname=) and unfortunately couldn't find any information from the manufacturer on whether or not the Hikvision supports dynamic IP addresses, so there's no guarantee it will work with your dynamic IP.
If we assume for a moment that the DVR does support a dynamic IP, though, all you'd have to do would be to port forward your router to get it out online. There are generally instructions on how to do this through the router manufacturer's tech support, however if not our sister website, Techstring.com, does offer router configuration for these applications for $75. Again, we cannot guarantee that your DVR supports dynamic IPs since the manufacturer's website has no information on the topic, but if it does then we could get you working. You can order that service at the following link:
http://www.techstring.com/product_p/dvr-router.htm
If you are unable to get the DVR working on a dynamic IP, though, I might suggest you consider an upgrade. Looking over the spec sheet, what I'm seeing here is a low-resolution DVR that is very light on features, meaning it probably won't be able to satisfy all of your requirements for a security system (ability to identify faces, set up intelligent motion detection, alarm notifications, etc). It seems like that Hikvision might be a DVR that will just create more problems in the future, so an upgrade might be wise.