Step 1: Differentiate implicitly.
\[
x^2 + 2x - 3y + 3 = 0
\]
\[
2x + 2 - 3\frac{dy}{dx} = 0
\]
\[
\frac{dy}{dx} = \frac{2x+2}{3}
\]
Step 2: Find slope at point $(1,2)$.
\[
m_{\text{tangent}} = \frac{2(1)+2}{3} = \frac{4}{3}
\]
Step 3: Normal slope.
\[
m_{\text{normal}} = -\frac{3}{4}
\]
Step 4: Equation of normal.
\[
y - 2 = -\frac{3}{4}(x - 1)
\]
\[
4y - 8 = -3x + 3
\]
\[
3x + 4y - 11 = 0
\]
\[
\boxed{3x + 4y - 11 = 0}
\]