How can convert 110ac to 12vdc
Look up the current requirements for your strip.  Most likely the site you bought it from will list how much current you need per length.  Multiply by the length you want to use.  
Buy a 12v power supply from a reputable company rated for more than this amount of current.  If the amount of current is very large (tens of amps), consider splitting the strip into multiple smaller strips and running them off of more reasonably sized supplies to reduce the risk from shorting a very high power supply.  If your laptop charger can provide that much current, you can use it.