Hi Cakiemommie (such a cute name!), if I were you I would concentrate on the wedding cake business primarily, because most people have a fairly decent budget for a wedding cake, as opposed to birthday cakes generally. Wedding cakes generally are less work than custom novelty/birthday cakes and have a much higher profit margin as a result.
The next thing I would look at is your website - is it well designed or staid/old fashioned? This is often the first port of call for potential wedding customers so it's one of the most important elements for a cake business. If it isn't want you'll like it to be, you can purchase beautiful website templates online for anything from $60-$100 and you can hire a designer on Elance.com (freelancer website) who should be able to do the switchover for you for about $100. It no longer costs thousands to have a beautiful website.
The next key issue is the photography on your website - so many people make outstanding cakes but then take terrible pictures of them for their website. Make sure when you finish a cake that you leave yourself time to take a decent pic before delivering it. (Wedding venues are often the worst place to photograph a cake because the full lighting isn't on until just before the guests are seated.)
To take a decent pic you need:
(a) to take it in daylight before 3pm at the latest (depending on where you are in the world and the season, shadow can start to develop late afternoon.). And the brighter the day the better.
(b) make a make-shift "studio" for yourself by buying a large sheet of plywood to use as a background and covering it with a sheet of pretty wallpaper in a neutral colour. (If you have a bigger budget, buy a selection of different wallpapers for different backgrounds to complement your cake colour schemes....my budget didn't stretch that far when I started!). Also lay a sheet of cream wallpaper under your cake and background before photographing i, unless you're using a very pretty table.
If the pics on your site aren't great, I would consider doing up a set of even just six "signature" designs as cake dummies and photographing them nicely, replacing your old ones with the new set to get you started. Then as you make additional cakes, get nice pics and add them to your collection also.
When, or if, you are already happy with your website, check where it ranks on a Google search for wedding cakes in your local area. If it doesn't rank highly, you might need to work on your SEO (Search Engine Optimisation - this is a whole topic in itself, you can either research it online and do the basics yourself or hire someone on Elance to do it for you.)
Finally, are you listed with your local wedding venues? ie on the list of recommended suppliers they give to wedding couples? If not, ring and request a meeting to introduce your business- bring samples and a portfolio book and dress in business attire. You might not get listed at all venues, but if another one of their suppliers lets them down, they'll replace them with you. That's what happened with one of my biggest local venues!
All of the above might be entirely not the issue and therefore irrelevant, if so, let us know and we'll have a brainstorm!