By low irons I'm assuming you're referring to 2,3, and 4 irons? If you're struggling with them (and a lot of people do, even scratch golfers), I'd suggest looking for a few hybrids to replace them. Most modern hybrids are adjustable, so you can change the loft on them. In terms of new irons, there are loads of game improvement (GI) irons out there designed to help high-handicap golfers. There are so many to choose from that it would be impossible to recommend you a specific set, and clubs are a very individual and personal choice.
I'd recommend getting a fitting and trying as many irons as you can. People slate American Golf for being poor at fitting and recommending the wrong clubs etc, but I haven't ever had any problems with them, plus they have a massive choice of clubs. Price-wise, they're a bit expensive but they do price match, so if you find something you like then just Google and find somewhere cheaper and they will almost certainly match the price.
Otherwise, get down to a local, reputable golf course that has a pro shop attached and get a fitting from the pro there. That's probably the option that most people would recommend, because you can go back to him if you have any problems or need adjustments in the future. Either way, the importance of getting clubs fitted cannot be understated, do not buy straight off the shelf. Fitting is absolutely worth the extra cost, and some places do it for free anyway.