I am wrestling with it now, because I cant justify spending 150EUR/month _and_ 1500EUR at year end to keep books and file returns. I have but six to ten invoices a year, and only myself as an employee; but such an animal doesn't seem very interesting to every relevant tax and accounting professional I've inquired with in Berlin. Perhaps it is the "English" premium, but at those costs I'm stuck spending more time than I care, at possibly greater risk than I am aware of, trying to do my own paperwork and books. In a system I mostly grok from (translated!) blog posts!
I have British friends in Berlin who run a bar and they pay around 800€/year. I don't know what your business is like, but I'd imagine a Bar is on the complicated side of things (lots of small transactions, changing personell etc).
You probably don't even need to do double-entry bookkeeping. If you look at your files from the last years, it should be pretty easy to figure out how to handle the different transactions. It only gets complicated when you start hiring people (as employees, not contractors) or have debt/investments.
Your accountant should at least let you do the monthly stuff yourself (usually very easy: just add the VAT you charged) and then do the yearly accounting for much cheaper, as long as you can get him/her the data in an easy=to-process format.
That isn't cheap. It keeps you above board, so that's worth its cost already, but offshoring is such a grey-area that it might not pay to even investigate it if you ever fell foul of any local regs. I once knew a Swede who successfully operated his business through a HK company, but how feasible that is now, and how well that fits into German regs is beyond me.
Your affairs sound so simple I'm surprised there isn't the equivalent of a low-cost, online-only type of accountant in Germany. Plenty of those here, at least, in GB.
My other thought was for you to enlist the help of a local to call around for quotes to confirm whether or not you are being quoted an "English premium".
I pay a bookkeeper to keep our books, and the accountant only comes into the picture at the end of the year when the company's accounts need to be filed and corporation tax needs to be paid.
Our company pays more for those services than your quote above, but if you're not incorporated as a company surely you could get a cheaper way to file returns?
At the least, you could take the monthly bookkeeping side of things away from your accountant.
