The funds could still be in the plan, or if you had below a certain balance, they may have sent it out to a rollover service, assuming that the plan is still in existence. Best option is to try your former HR, or look for contact information on an old statement from the plan.
The balance may be lower than you recall because of their vesting schedule, where company contributions were concerned.
If the plan is still active the money should still be in your account and invested the same way you left it. If the company terminated the plan, automatically rolled the money, or cut you a check you should have received notice. 401k plans are great for current employees, but if you are no longer employed it is generally best to roll the money to your new employer plan or an IRA. Even though you are no longer employed the plan provider should still be sending you statements. Your statement will have contact information for the plan provider so you can learn more about your 401k account.
Perhaps this article is helpful http://www.brightscope.com/financial-planning/advice/article/24529/10-Ways-To-Find-An-Old-401K-Plan/
I would contact the plan administrator (Fidelity, Vanguard, etc.) to get a current statement. You can then roll these funds over to your new 401k or an IRA. Either way, I would consider doing so to make it easier to manage your money. Since Rummel was a smaller company I doubt they are actively managing the funds within your 401k for the best performance and fees available.