Oven: advice wanted

My oven has been dying for a long time. Aside from the continuously firing igniter, which has been going I think since I moved in, the lower element died a couple of years ago, meaning dishes only get cooked from the top down; and now the rubber sealing around the door has come away, leading to heat loss. I tried to repair what was left (part has vanished) with vulcanising rubber glue (after checking online that it was heat-stable!), but it didn't hold.

I've put up with longer cooking times for a few weeks for the smaller items I make for just myself, but last night I tried to make a larger dish (a kugel to take to Yedid Nefesh tonight), and rather than taking an hour as the recipe said, it took two hours and still only the top part was done. So I turned the dish upside down on tin foil and stuck it back in the oven for a further half hour (which was as long as I could spare to let it cool down enough to go in the fridge before I went to bed), but when I tried to turn it back over, it fell apart, because the middle was still not sufficiently cooked. (I'll stick it back in the oven when I come home this afternoon for the forty minutes until Shabbos comes in, and after that it'll just have to do.)

So, something needs to be done, but the question is what. I got as far as looking at replacement ovens this summer, but the type I wanted—gas on top (because electric hobs take too long to heat up and cool down), and electric inside (because I'm not leaving a gas oven on overnight if I'm entertaining enough people on Shabbos lunch that my hotplate isn't big enough for all the food)—turned out to be the most expensive, and I was disinclined to spend a lot of money when I'm intending (or so goes the theory) not to be in the flat for much longer.

So, the options are: Get someone in to repair my oven, get a new oven, or get a secondhand oven. Do you have any advice?