dual booting pc

HI,Here's my problem,i a DELL E 521 with 2 HDD'S one older HDD with WINXP on it,the other one is a new SEAGATE SSDH w/1TB HDD.
I would like to transfer the WINXP OS and all of the data to the WIN 7 OS HDD,but i understand if i were to
do this i would overwrite the WIN 7 OS and data is this true.
It has been suggested to clone the WINXP and transfer it that way and also the matter of the MBR has come a few times saying the MBR has to be in the first OS to boot up as you can see i am new territory as
far as doing a dual boot and would like to accomplish without wiping all that i have both HDD'S off them.
I ALSO HAVE A 500GB w/d external HDD i have ideas from my research on Google and once i get clear in my mind i will probably see how easy it was to do

Save an XP backup image to external using free Imaging with free Macrium after condensing XP as much as possible by deleting old files, running CCleaner and defragging using free Puran Boot Time Defrag w/Disk Check to get at System files not running at boot.

Shrink C to create a space to apply the Macrium image, which you can do from Win7.

Once XP is imaged over to the SSD, power down to unplug all other drives, install EasyBCD (click Download - no Name or Email required) to add XP to a Dual Boot menu.