Obtain the current value of the seed used by the random number generator

You may get the current state of the random generator with

gs = Random`GetRandomState[];

This can be loaded back into the generator later with

Random`SetRandomState@gs;

Then you can continue from where you left off.

Note that these are undocumented functions and as such there is no guarantee that the functionality will remain the same in future versions of Wolfram Language.

Hope this helps.