Currently I am developing a salesforce integration solution using a .net .I have a developed a console application for that and scheduled it running every 5min.That mean I am requesting all updated or inserted record IDs from relevant objects with particular time period in every 5min But sometime I had a exception as REQUEST_LIMIT_EXCEEDED: TotalRequests Limit exceeded even there is no any insert or update that particular objects.

So I want to know.........

   1)Number of request mean count of access that objects even there is no any update or insert,if that so how can I solve this problem ?

   2)How can I do a real time integration with salesforce..?(In my case it take 5min to update other party)

immediate solution pls.......!

I am exceeding API request Limit, I am using Salesforce Professional Edition and updating records in it from a .Net Application. 

.Net application updates multiple object at a time (Accounts, Contacts, Opportunity, Cases) 

I have tried to make my .net code efficient , but still I am exceeding limit, and than I have to wait 24 hours until it releases the limit. Is there any way to Increase API limit or any other way?