it takes this command about 2 mins to return the data as there is a lot of data
Probably, Bad Design. Consider using paging here.
default connection time is 30 secs, how do I increase this
As you are facing a timeout on your command, therefore you need to increase the timeout of your sql command. You can specify it in your command like this
// Setting command timeout to 2 minutes
scGetruntotals.CommandTimeout = 120;