Typically, your 401k provider will provide you with a regular (monthly or quarterly) paper statement or a website that will have all the information you need. I suggest you reach out to your 401k provider to find out how to access the information you are looking for.
Ryan's answer is spot on. I would contact your HR department for the website to login. From there you can not only view your balance but also make adjustments to how much you contribute. Further, you will be able to adjust your investment portfolio.
Does that make sense? Please let us know if we can be of further help.