How I check in Apex Class, as given  string year parameter is grater then or equal to current year

APEX

List<Contact> contactList = [SELECT firstname,lastname,Current_Fees_Due__c,Id,A_Level_Year__c from Contact WHERE Contact_Type__c = 'Student' AND Tuition__c='Customer' AND A_Level_Year__c>='%Current Year%'

ORDER BY Name ASC];

Note: A_Level_Year__c = '2012' [ parameter is strin g format]

Hi, 

In my salesforce i m using one Button link, there I gave follwing URL. When I am clicked this button does not pass value wherever i m using paaing values.

For examble: Firstname={(Contact.Firstname)} --> passing the value like {(Contact.Firstname)}

but actually i want firstname of corressponding customer.

http://localhost/MIndleverQBWeb/sfpage.aspx?username='test'&password='test'&alevel={(Contact.A_Level_Year__c)}&contacttype={(Contact.Contact_Type__c)}&Firstname={(Contact.Firstname)}&Lastname={(Contact.Lastname)}&Email={(Contact.Email)}&Mobile={(Contact.Mobile)}&Address={(Contact.MailingAddress)}

I am using Saleforce Production account for student maintence, there i handling Student, teacher, Class and Attendance records. Now I am also using Quickbooks for invoice purpose.

So Now I want to migrating customer data from salesforce to quickbooks under some condtions also

I ll provide some new button in salesforce, in feature we will add a new student record, that time click this button if condtions are matched automatically it move to Quick books. 

what kind of Class I need to use.. how to use?? Can you please explain me...

I am using Saleforce Production account for student maintence, there i handling Student, teacher, Class and Attendance records. Now I am also using Quickbooks for invoice purpose.

So Now I want to migrating customer data from salesforce to quickbooks under some condtions also

I ll provide some new button in salesforce, in feature we will add a new student record, that time click this button if condtions are matched automatically it move to Quick books. 

what kind of Class I need to use.. how to use?? Can you please explain me...