There is no overclocking "program" which will do the honours for you. The closest thing to that is the desktop overclocking utility which is found on many high end motherboards. But even that is not as efficient as BIOS overclocking. Nothing beats that.
 Seeing as you are getting a pre-built system, there is 99% chance that you won't be able to do any overclocking due to:
1) Crap motherboards
2) The OEM builders themselves don't like users overclocking (since this might mean more claims under warranty due to faster wearing of parts), & so they provide you with a closed system which you cannot tinker with (& Dell is particularly hard-assed about this).