You have no more than 2 solutions:
1) Perform a Registrant Transfer at NSI at :
(If I remember correctly, requires the services of a Notary)
2) Shop around and transfer the domain name to a different registrar, then transfer ownership through them. Each registrar has different rules and procedures. Read their FAQs carefully.
You need to renew that domain name. NSI is famous for auctioning unpaid domain names, and it would be a shame to lose it that way. Their databases are rarely up to date, so you may see that the domain name still exists, while in fact, it has expired.
To have an up to date look, try the "Whois lookup" at www.corenic.org . All registrations, and expirations show up anywhere from 8 to 24 hours there, while on most other databases, you see changes 48 hours later.
Check Core 2 times a day, just to be sure. Remember, if the name has expired, millions of people can buy it before you!And who knows, maybe someone else is keeping their eye on your domain, waiting to pounce on it the moment it is "freed". Sometimes the whois at core doesn't give much information. It is useful for knowing if a name is taken, but if you want detailed information, www.betterwhois.com will give it to you.
Here is where you can find urls for other registrars: