Yes, if you upgrade your account you will receive more contact lookups to use each month. For example if you are currently on the Bronze plan you can upgrade to the Silver plan. And upgrading is easy. Just go to the 'Pricing' tab in your account and select the plan you wish to upgrade to.
Purchase one-time credits: Accounts that are currently subscribed to a monthly or annual plan are also eligible to purchase one-time lookup credits by contacting firstname.lastname@example.org. Let us know how many lookup credits you will need to get through the month and we can assist you with the purchase.