There's been several people who suggested using a high-level synthesis tool to convert your software (c/c++) directly to HDL (verilog/VHDL) of some kind. This can work and I've been on this task and seen it's output before. The catch is; unless that software was expressly and purpose written to describe hardware (by someone who understands that hardware and it's limitations and how that particular converter works), it almost always makes awful and extraordinarily inefficient hardware.
Case in point - we had one algorithm developed in Simulink/Matlab that needed to end up in an FPGA. After 'pushing the button' and letting the tool generate the HDL, it consumed not just 1 but about 4 FPGAs worth of logic gates, RAMs, and registers. Needless to say the hardware platform only had one FPGA and a good portion of it was already dedicated to platform tasks so only about 20% was available for the algorithm. We got it working after basically re-implementing the algorithm with the goal of hardware in mind. The generation tool's output was 20 times worse than what was even feasible. If you're doing an ASIC you can just throw a crap-load of extra silicon at it, but that gets expensive very quickly. Plus closing timing on that will be a nightmare.
My job recently has been to go through and take algorithms written by very smart people (but oriented to software) and re-implement them so they can fit on reasonably sized FPGAs. It can be a long task sometimes and there's no push-button solution for getting something good, fast, cheap. Techies usually say you can pick two during the design process, but when converting from software to hardware you usually only get one.
Granted this all varies a lot and depends heavily on the specifics of the algorithm in question. But the most likely way to get a reasonable estimate is going to be to explain the algorithm in detail to an ASIC/FPGA engineer and let them work up a prelim architecture and estimate. The high-level synthesis push-button tools will give you a number but it probably won't be something people actually want to build/sell or buy.