Of the other remaining capital expenditures, we've spent $7 million on the sustaining capital expenditures and $58 million on revenue-generating capital expenditures, the latter consisting of $30 million on existing sites and $28 million on the construction of new sites, primarily distributed antenna system deployments. Further, during the second quarter, we used $51 million of cash to purchase a portion of our 9% senior notes and 7.75% senior secured notes, including make-whole costs at prices we found attractive relative to these bonds' respective call dates.
We ended the second quarter of 2012 with total net debt-to-last quarter annualized adjusted EBITDA of 5.5x and adjusted EBITDA-to-cash interest expense of 3.1x. As you saw in our press release last night, we reached an agreement with T-Mobile USA to extend the remaining term on all 7,300 existing leases to 10 years and granted T-Mobile rights to upgrade certain towers with radio equipment in connection with their network modernization plan. We expect this agreement to contribute approximately $20 million in site rental revenue to our second half 2012 results.
Moving to the outlook for the third quarter and full year 2012 as shown on Slide 7 and 8. We expect site rental revenue of between $530 million and $535 million and adjusted EBITDA of between $387 million and $392 million for the third quarter of 2012.