Too much data for Analysis Service import

Hi,

Am currently moving one of our company's dashboards from Excel over to Power BI, one tab has a connection to a cube data source using analysis services. 

Because it usually has quite a few slicers with different demographic data, this translates to many, many rows when importing to Power BI and it will not apply changes (adding items / dimensions to the table in power bi) in order for me to get on with building the dashboard slide.

Is there either a way to increase the amount of data / raise the time out limit of pulling this data from our servers, or another work around (preferably not through another spreadsheet or anything, I would like to have this so I don't need to update it at the beginning of every month)

Thanks

Fraser