Can I use both at the same time?.

No. RCE is a power action and PW is a ranged combat action. And even if they were the same type of action you could only use the action to activate one of them.

It's a little lengthy but the first thread in the rules section is devoted to explaining exactly this. Here is the link in case you get some free time, it will take a bit to get thru it but it should help clarify what you aren't sure of at the moment.

http://www.hcrealms.com/forum/showthread.php?t=231644

Yes I better read that one I'm very green at combo powers.