As we have been reporting since the start of these talks, Virgin Mobile USA (NYSE: VM) has finally announced the acquisition of troubled MVNO Helio. We originally broke the news of talks between the two companies back in May. The acquisition will cost Virgin Mobile a paltry $39 million, paid in limited partnership units equivalent to 13 million of its shares, currently valued at $2.99. In addition, the company will take on a fresh $50 million of investments from British parent Virgin Group and SK Telecom (NYSE: SKM) ($25 million from each) at a price of $8.50 per share. VMUSA intends to use the proceeds from these strategic investments by SK Telecom and Virgin Group to pay down a portion of its existing senior secured loan. SKT and Virgin Group have also agreed to provide an additional $35 million and $25 million, respectively, to increase VMUSA’s existing revolving debt facility, which will support the company’s ongoing growth. Full coverage at our sister site mocoNews.net…