(0) Can you link to the product?
(1) When did you start and what has the growth trajectory been (e.g., weekly growth rate)?
(2) Is there some marginal cost other than server space that is limiting growth?
1. I started part time about a year ago, full time about 6 months ago. I recently completed the survey (I think created by Sean Ellis; with a few tweaks), and implemented based on that. This resulted in a spike in growth in the past week, but I fear that'll only hurt if the product stays as slow as it is now on the current hosting situation.
2. Server space is the only cost limiting growth, unless the stats have fooled me and it's really not at PM fit; in which case marketing would be another cost.
How would you rate your skills as a developer? If you're having performance issues with very little traffic it might be more worthwhile to include someone with better technical skills than you rather than raising money. Scaling is a linear thing based on the number of machines and if you already have some slow warts you'll burn through any money that you raise very quickly. Not to mention, an accelerator or Angel hearing about your technical woes this early will probably require you to have a technical partner anyway.
My other thought is you might be cheap. There's nothing wrong with that, it's good to be cost conscious but if you have demand you have to scale. Saying that server space is limiting growth is a very odd limitation to have.
Also you shouldn't have performance issues with your numbers, you should be able to comfortably run a site with 100k users off a cheap server. Maybe you should spend some time analyzing the source of your performance issues.