If most common TLDs are not available with your required name, you can choose alternate TLDs such as .biz, .tv. But , you need to make sure that your domain name doesn't contain any trademarked phrases or you could lose it to the company that holds such a trademark later on (rulings usually go in favour of trademark holders).
If you have sufficient money you can try to offer to buy it from its current holder. If this domain name has expired or it might expire soon, there are services that will try to grab it before anybody else has a chance to do it. For more information regarding this issue, please contact us.