Aggregate daily level data to weekly level in R

I have a huge dataset similar to the following reproducible sample data.

   Interval    value1  2012-06-10   5522  2012-06-11  48503  2012-06-12  46424  2012-06-13  41325  2012-06-14  41906  2012-06-15  41867  2012-06-16  11398  2012-06-17   4909  2012-06-18  515610 2012-06-19  443011 2012-06-20  444712 2012-06-21  425613 2012-06-22  385614 2012-06-23  116315 2012-06-24   56416 2012-06-25  486617 2012-06-26  442118 2012-06-27  420619 2012-06-28  427220 2012-06-29  399321 2012-06-30  121122 2012-07-01   69823 2012-07-02  577024 2012-07-03  510325 2012-07-04   77526 2012-07-05  514027 2012-07-06  486828 2012-07-07  122529 2012-07-08   67130 2012-07-09  572631 2012-07-10  5176

I want to aggregate this data to weekly level to get the output similar to the following:

   Interval           value1  Week 2, June 2012  *aggregate value for day 10 to day 14 of June 2012*2  Week 3, June 2012  *aggregate value for day 15 to day 21 of June 2012*3  Week 4, June 2012  *aggregate value for day 22 to day 28 of June 2012*4  Week 5, June 2012  *aggregate value for day 29 to day 30 of June 2012*5  Week 1, July 2012  *aggregate value for day 1 to day 7 of July 2012*6  Week 2, July 2012  *aggregate value for day 8 to day 10 of July 2012*

How do I achieve this easily without writing a long code?