You're going to have to approach this a little differently than you would a hamstring pull. With other muscle strains, particularly distal muscles (further towards the extremities), you body does a pretty good job at forcing your to protect those muscles by inducing changes in movement or gait. When it's a core muscle though, the protection is still there, but it's a muscle utilized in just about every movement as a mover or a stabilizer, so it sees far more action throughout the day (and even some at night), meaning it has far less time at rest for repairs.
R.I.C.E. (Rest, Ice, Compression, Elevation) is still going to be the way to go in treating this, but you may find yourself requiring more rest and time than you would for a hamstring strain.
Recovery may also depend on the severity of the strain. If you aren't seeing ANY improvement after two weeks, then a trip to the doctor may be in order as you may be suffering from a higher grade strain, some of which require surgery to repair. If you get to this point, you may also be looking at some type of herniation. Just keep a close eye on your pain levels and range of motion so that you can track improvement, and don't push it too hard. Better to take the time off and recover fully than delay recovery or even cause further injury by overworking it.
Best of luck!