Obviously, you think your equipment is limiting you? It's not. It's not the equipment. It all has to do with technique. So if you are a crappy engineer, it doesn't matter what your equipment is it'll still be crappy. There is your limiting factor.

Additional hardware? You really don't need any additional hardware. Though having a monitoring controller that allows for different sources of input to go to different sets of monitor speakers, is a handy device to have and purchase. Otherwise you only need to take the output of your audio card and feed it to your monitor system, amplifier and speakers or powered monitors.

If you want that warm analog like sound, the LA-610 would be a great piece. No point in waiting for the Apollo to go PC. If you want more of that modern state-of-the-art sound, RME or the Steinberg do hickey. But that's crispy sounding.

If you are an arranger/composer and you're finding that latency is a problem, join the club. Most computer audio interfaces have issues with latency, when effects are running. They really weren't designed with the power for processing while recording/overdubbing. Today, units like the Apollo, have an onboard processor, a special CPU, for real-time effects without latency. Other devices like the PreSonus Audio Box USB 2.0 version, offers real-time effects, from the computer's CPU with very low latency. Low enough that it should not be an issue. This is where your current devices fall on their face. Can't do what you want to do because it's not designed to do what you wanted to do. So even that new RME or even the UA device, may not be able to give you the effects you want during your overdubbing, composing/arranging? All those effects are designed to be put in after you're done with the recording process. Not during it. That's where these new thunderbolt and other FireWire and USB 2.0 devices start to come in. They'll offer lower latency than what you are currently experiencing.

Other than that, the additional equipment that you might want, will be additional preamps, equalizers, dynamic range limiters, digital reverbs and effects, like any real professional studio would have. That and the mixer/console. What makes you think that you can do all of this with the prize you get out of a cracker Jack box for free? Not going to happen. So it's one thing to be a composer/arranger, it's a whole other thing to be a professional engineer/mixer. Of course you're going to have problems, you're not an engineer. That's why composers/arranger's, generally deal with actual recording engineers to take care of all the problems. If anybody could be a recording engineer, then everybody would want to be one.

I don't arrange anything but my control room.
Mx. Remy Ann David