At the minimum, you need Lightroom 4.1 Or Camera Raw 6.7 to have support for that camera. Camera Raw 6.7 is only compatible with Photoshop CS5. If you're going to upgrade Lightroom then you might as well go to Lightroom 5 because it will be difficult to find older versions. If you don't want to do any software upgrading you can use the DNG converter to create DNG copies of your raw files. As it stands right now with what you have, you have no support for your camera.
Jim's reply provides the info you require and the workaround to be able to use LR 3 on your camera's raw files. Just be aware that LR 3 is now a bit dated and does not have the latest technology available from Adobe to process the raw files. Good idea to consider upgrading to LR 5.
Thanks for the info guys, this is very helpful! Do you think I should I just upgrade to Lightroom 6? Is there much of a difference between LR 5 and LR 6?
Also, can I upgrade all adobe programs (LR, PS and BR)? Where do I go about upgrading?
Unless I missed an announcement, today, LR6 isn't available, yet, right? Only Adobe employees and beta testers would know what LR6 does differently at this point and they're all sworn to secrecy.
LR5 is available as a standalone version.
PS-CS6 is available as a serial-number-licensed version.
PS-CC + LR5 are also available as a Photography Plan subscription for $10/month with a minimum OS versions of OSX 10.7 (and probably 10.8, soon) and Windows 7.
Bridge is part of PS, not a separate program.
LR5 standalone and LR+PS-CC plan are both available on this page: http://www.adobe.com/products/catalog/software.html
As with any new Adobe software, it might be wise to run it in trial mode for a few days/weeks to see if it works well with your computer, before purchasing and finding out you might need a new computer, first.
HAHA!! Oops... I must have been dreaming about LR6.
Can I just upgrade my version on those websites you provided or do I need to purchase again?
Thank you so much for all of your help!!!
Updates within the LR3.x series are free. UpGRADES to newer LR4 or LR5 are paid..